Qualifications : BE (
Location : Room 2.4,
Communications : Telephone +353-1-608-2029, Fax
+353-1-677-2204, Email Dan.McCarthy@cs.tcd.ie
Computer
Arithmetic, parallel architectures & processing, history of numbers and
computation, computistics, lunar and solar cycles, astronomy, chronology, the
chronicles of Eusebius, Jerome, Sulpicius Severus, Prosper, Bede and the Irish
annals, the Paschal controversy.
Recent publications - click for abstracts:
1987 – ‘The
"lost" Irish 84-year Easter Table rediscovered’
1993 – ‘Easter
Principles and a Fifth-Century Lunar Cycle used in the British Isles’
1994 – ‘The
Chronological Apparatus of the Annals of Ulster AD 431-1131’
1994 – ‘The
Origin of the Latercus Paschal Cycle of the Insular Celtic Churches’
1995 – ‘A
Re-evaluation of the Eastern and Western records of the Supernova of 1054’
1996 – ‘The
Lunar and Paschal Tables of De ratione paschali Attributed to Anatolius of Laodicea’
1997 – ‘The
Biblical Chronology of James Ussher’
1997 –
‘An Evaluation of Astronomical Observations in the Irish Annals’
1998 –
‘Astronomical Observations in the Irish Annals and their Motivation’
1999 – ‘The
Chronology of the Irish Annals’
1999 – ‘The Status
of the pre-Patrician Irish Annals’
2000 – ‘À propos du synode de Whitby. Étude des
observations astronomiques dans les Annales irlandaises’
2000 – ‘The
Chronology of S. Brigit of Kildare’
2001 –
‘Topographical characteristics of the Vita Prima and Vita Cogitosii Sanctae Brigitae’
2001 – ‘The Chronology and Sources of the Early Irish
Annals’
2002 – ‘The chronological
apparatus of the Annals of Ulster AD 82–1019’
2003 – The ante-Nicene Christian Pasch: De ratione paschali – The Paschal tract of Anatolius,
bishop of Laodicea
2003 –
‘Al-Khwarizmi’s sine tables and a Western table with the Hindu norm of R=150’
2003 – ‘On the
shape of the Insular tonsure’
2003 –
Annals & Chronology of Irish history
2003 – ‘The
emergence of Anno Domini’
2004 – ‘The
Original Compilation of the Annals of Ulster’
2005 –
‘Irish chronicles and their chronology’
2005 –
‘Chronological Synchronisation of the Irish Annals’
2005 –
‘Collation of the Irish regnal canon’
2008 – The Irish Annals: Their genesis, evolution
and history
2009 – Review of
Thomas M. Charles-Edwards, The Chronicle
of Ireland: Translated with an introduction and notes
2010 – ‘Bede’s
primary source for the Vulgate chronology in his chronicles in De temporibus
and De temporum
ratione’
2010 – Review
of Nicholas Evans The Present and the Past in medieval Irish
chronicles
2011 – ‘The study and use of numbers in early Irish monasteries’
2011 – ‘A facsimile edition of the Annals
of Roscrea’
2011
– ‘On the arrival of the Latercus in
Ireland’
2012 – The Annals of Roscrea – A diplomatic edition
2013 – ‘Ruaidhrí Ó Casaide's contribution to the Annals of Ulster’
2013 – ‘TCD MS 1282 (The Annals of Ulster): a scholar's book and exemplar’
2014 – ‘The illustration and text on the Book of Kells folio 114rv’
2014 – ‘Dalkey Quarry
Tramway 1815-c.1855’
2014 – ‘The contribution of Armagh scholarship to
the Annals of Ulster’
2015 – ‘The
Chronology of Saint Columba's Life’
2015 – ‘On
reconstructing medieval Irish chronicles’
2016 – ‘Offprints of Ada Lovelace’s translation of Luigi
Menabrea’s account of Charles Babbage’s Analytical Engine, incorporating an
offprint by Babbage’
2017 – ‘Analysing
and Restoring the Chronology of the Irish Annals’
2017 –
‘Representations of tonsure in the Book of Kells’
2017
– ‘The Paschal cycle of St Patrick’
2018 – ‘Recovering years lost from the Irish annals’
2018 – ‘The Genesis and Evolution of the Irish Annals to AD 1000’
2021 – ‘The Council of Nicaea and the Celebration of the Christian Pasch’
2022 – ‘Tonsure’ – The Brill Encylopedia
of Early Christianity Online
2022 – ‘Sulpicius Severus’s Construction of his
84-year Paschal table’
2023
– ‘The Zeitz Paschal Table of
AD 447’
List of Abstracts -
‘Stonehenge
and pi’, D.P. McCarthy, The Mathematical Gazette vol. 71, no. 458 (Dec.,
1987), 293-4.
Abstract. In
1666 John Aubrey remarked on the fifty-six pits spaced around the main monument
of Stonehenge, and in 1978 Alexander Thom surveyed these and showed that they
form a very regular fifty-six sided polygon of mean radius 141.8 feet. This
note shows that the number 56 provides two good, decimally convenient,
approximations to pi, namely 562/1000 < pi < 562/1000
+ 56/10000, with differences respectively of 5.6×10-3 and 7.3×10-6.
‘The
‘Lost’ Irish 84-Year Easter Table Rediscovered’, D. Mc Carthy & D. Ó
Cróinín, Peritia 6-7, (Cork, 1987-8), 227-42.
Abstract.
The Paschal controversy in the British Isles centred on the use of an 84-year
Easter table, which was abandoned by
‘Easter
Principles and a Fifth-Century Lunar Cycle used in the
Abstract. The computational principles underlying the
Paschal table, or latercus, found in the manuscript Padua, Bibl. Antoniana I.27 f. 76r–77v, are closely analysed and the
details of the mechansims of its embolism, bissextile
and saltus are resolved as closely as possible. With this information it is
possible to eliminate all of the scribal errors from the table and, thus
restored, the table is presented in full. From this can be seen that the
‘The
Chronological Apparatus of the Annals of
Abstract. This paper demonstrates that the
chronological framework of the Annals of Ulster is a combination of two
different systems: one based on January AD dating (nativity era), the other
based on March AD dating (incarnation era). This discovery explains the
discrepancies in the dates, and vindicates Ussher's analysis of the dating
criteria against Bartholomew Mac Carthy's later
critique. The introduction of March AD dating is pinpointed to the eleventh
century, and is related to contemporary political and ecclesiastical
developments. The original chronological apparatus is restored and some of the
literary sources are also identified. The date and place of compilation for the
original are identified as
‘The
Origin of the Latercus Paschal Cycle of the Insular Celtic Churches’, D. Mc
Carthy, Cambrian Medieval Celtic Studies, 28 (1994), 25-49.
Abstract - The
‘A
Re-evaluation of the Eastern and Western records of the Supernova of 1054’, A.
Breen and D. Mc Carthy, Vistas in Astronomy, 39(1995), 363–79.
Abstract. The Chinese and Japanese records are our primary
evidence of the supernova of 1054. But their evidence is not entirely
consistent, and recent scholarly discussion of them has not yielded clear-cut
results. We have therefore re-examined the original sources in some detail in
order to determine their relative historical value and to arrive at as close a
determination as possible of the appearance of the event itself. We have
established from the Chinese sources that, on the authority of the Chief of the
Astronomical Bureau at K'ai-feng, a guest star was
first sighted between 9 June and 7 July 1054 to the north-west of Zeta Tauri; it became as bright as Venus, was visible in
daylight for 23 days and did not disappear from sight until just before 17
April 1056. All this location, duration and brightness data points to this
guest star as the supernova progenitor of the Crab nebula. When the Japanese
texts are considered the date 4 July 1054 emerges as the most likely date for
the first sighting of this supernova. Recent claims for both Middle-Eastern and
Western European records are evaluated in the light of this result.
‘The
Lunar and Paschal Tables of De ratione paschali Attributed to Anatolius of Laodicea’, D. Mc
Carthy, Archive for History of Exact Sciences, vol
49, no 4 (1996), 285–320.
Abstract. The lunar and Paschal tables in the text De
ratione paschali have
been critically discussed by numerous authors over the last 100 years without
their inter-relationship ever being considered or understood. Now, as a result
of the discovery of the
‘The
Biblical chronology of James Ussher’, D. Mc Carthy, The Irish Astronomical Journal vol. 24, no. 1 (Jan. 1997), 73–82.
Abstract. Interest in James Ussher and his chronological
work saw a re-awakening as the date of the 22nd October 1996
approached and it was realised that we were commencing the six thousandth year
from Archbishop Ussher’s estimated date of Creation, viz. the beginning of the
night of the 22nd October 4004 BC. In the popular press some,
playing on the inherent uncertainty of our existence, suggested that Ussher had
predicted that the world would end on the evening of 22nd October
1996; thus the Irish Times headline
of this date ‘An early tea would be advisable as the world may end at 6 p.m.’.
However, examination of Ussher’s published works and manuscripts shows that
while he strongly reflected the millenarian beliefs of his own time that
significant events fell at intervals of one thousand years, he provided no
precise time of day for Creation and no prediction of the time and date of the
Last Day. In fact the precise time of Creation of 6 p.m. represents an
interpolation made by the
‘An Evaluation of Astronomical Observations in the Irish Annals’, D. Mc
Carthy & A. Breen, Vistas in Astronomy, vol
41, no. 1 (1997), 117–38.
Abstract. The astronomical entries scattered through
the Irish annals have been examined in a serious astronomical context by R.R.
Newton as part of his research into the accelerations of the earth and moon,
and by D. Schove and A. Fletcher, as part of the
Spectrum of Time project. They have never, however, been fully collated and
examined as a whole as this paper undertakes to do. What emerges is a body of
records from 442 to 1133 documenting eclipses, comets, aurorae, volcanic dust
clouds and possibly a supernova; from 627 to 1133 all of these records are of
observations made in or near Ireland, and most of them are accurate in their
chronological and descriptive details. Analysis of the details of these records
implies that, at least from the seventh to the eleventh centuries, careful and
sustained observation and recording of astronomical phenomena were conducted in
some Irish monasteries, and it is clear that the underlying motive was
religious and specifically eschatological, i.e. to detect the first signs of
the end of time as prognosticated in the Book of Revelation. Critical
examination of this data allows us to throw new light on the circumstances of
the Synod of Whitby in 664, to identify the date of the eruption of the volcano
Eldgjá in
‘Astronomical
Observations in the Irish Annals and their Motivation’, D. Mc Carthy & A.
Breen, Peritia 11 (Cork 1998), 1–43.
Abstract. This paper presents the same material as is
presented in An Evaluation of Astronomical Observations in the Irish Annals,
but it concentrates on the textual and historical issues relating to the
material. Thus the original texts of all the entries are reproduced and a much
more detailed textual treatment is given of the entry found under 1054 and the
historical background to the Synod of Whitby and its relationship to the solar
eclipse of 664.
‘The
Chronology of the Irish Annals’, D. Mc Carthy, Proceedings of the
Abstract. The chronology of much of the Irish annals
has hitherto been most uncertain, particularly from the fifth to the eighth
centuries, which has seriously hindered their use as historical sources. This
paper demonstrates that the oldest chronological apparatus preserved in these
annals is the kalend-plus-ferial and, further, that the ferial data recorded in
the Annals of Tigernach and Chronicon
Scotorum may be restored and constitutes a cogent
sequence from the Incarnation up to the middle of the seventh century. When
this chronology is calibrated using events for which we have indepedendent chronological information it emerges that
thirteen kalends were removed from the Iona Chronicle between the AD
years 424-664, and thus we may recover the nearly all of the original
chronology of that chronicle. Collation of this chronology with those of the Annals
of Ulster and Inishfallen shows
that both preserve derivative and corrupted chronologies; this collation has
been made available on the Web at -
https://www.cs.tcd.ie/Dan.McCarthy/chronology/synchronisms/annals-chron.htm
A copy of this paper is
available as a PDF file for down-loading from the Royal
Irish Academy website.
‘The
Status of the pre-Patrician Irish Annals’, D. Mc Carthy, Peritia
12 (1998), 98–152
Abstract. This paper investigates the question of the
sources and dates of the pre-Patrician material found in the annals of
Tigernach and Inisfallen, firstly by reviewing all
the contributions which have been made over the last century. From this it
emerges that whereas analysis of the non-Irish material has resulted in
significant progress, exploration of the Irish material has proven both
difficult and singularly unproductive. Consequently a careful examination of
the chronological structure and textual details of part of the Roman imperial
succession has been made, which discloses that it had been compiled by conflating
Eutropius’ Breviarium
ab urbe condita with Jerome’s Chronicle.
Next, textual collation with Bede’s Chron. Mai. shows that, rather than
the annals having been derived from Bede, as has been generally assumed, in
fact both pre-Patrician AT and AI, and Bede, all derive from a common source.
The evidence shows that, while Bede’s text is generally less textually corrupt,
the annals preserve both more of the content of the original source, and its
chronological apparatus as well. Next, examination of the Alexandrian episcopal
succession found in AT shows that it had been derived directly from Rufinus’ Ecclesiastical History, and details of the
errors suggest that it was he himself who constructed it. Finally, examination
of the Hebrew succession in Bede and AI reveals divergences from Jerome’s
chronology that could not plausibly be the work of Bede, but are all
appropriate to Rufinus. Hence, as a working
hypothesis it has been proposed that Rufinus compiled
a chronicle in the first decade of the fifth century, which travelled to
Ireland with the 84-year Paschal table of Sulpicius Severus, whence it was used
in Iona in the mid-sixth century as the basis for the Iona Chronicle.
Tables of both the Roman imperial reigns and the Hebrew succession are
available at:
https://www.cs.tcd.ie/Dan.McCarthy/chronology/synchronisms/annals-stat.htm
‘À propos du
synode de Whitby. Étude des observations astronomiques dans les Annales
irlandaises’ D. Mc Carthy & A. Breen, Annales de Bretagne et des Pays de
l'Ouest vol 107, no.3 (Rennes 2000).
This is essentially a
translation to French of the paper published in 1997 as An Evaluation of Astronomical Observations in the
Irish Annals in Vistas in Astronomy, vol
41, no. 1 (1997), 117–38.
‘The
Chronology of S. Brigit of Kildare’, D. Mc Carthy, Peritia
14 (2000), 255–81.
Abstract. This paper undertakes a critical
chronological and textual analysis of all the annalistic entries bearing on the
life of S. Brigit of Kildare. From this it emerges that AT and CS have best
preserved the chronology originally given to Brigit in the Iona Chronicle
which placed her death at AD 524 aged 86 years, whereas AU and AI transmit a
later tradition subsequently interpolated into the Iona Chronicle that
she died aged 70 years. It is argued that the author of the original Iona
Chronicle entries was S. Columba, a competent computist and
near-contemporary of Brigit, and hence that his chronology of Brigit is
trustworthy. To check this, a chronological evaluation of the earliest surviving
Vitae S. Brigitae reveals that the chronology
of all the individuals found jointly in the Vita I and the annals is
consistent, implying that both sources have transmitted a chronology which is
essentially correct, a result which supports the historical priority of Vita
I over Vita II. Finally examination of the context of Cogitosus’ date for Brigit’s death shows that he aligned it
to correspond with existing non-Christian celebrations already held in Kildare.
‘Topographical
characteristics of the Vita Prima and Vita Cogitosii
Sanctae Brigitae’, D. Mc Carthy, Studia Celtica XXV
(2001), 245–70.
Abstract. The two oldest lives of St. Brigit of Kildare
are the anonymous Vita I and Cogitosus’ Vita
II, but scholars have disagreed as to which is the oldest. However
evaluation of all of Vita I’s topographical references reveals that it
maintains a virtually continuous location for her entire active adult life. It
thus mirrors topographically the chronological consistency with annals already
demonstrated for Vita I. Since these topographical and chronological
elements are evidently independent they must derive from a common tradition
which is earlier than that of the annals, that is, the later sixth century. On
the other hand Vita II is topographically blank but when Vita I
is used to locate Vita II’s
parallel episodes, all but three are located in Laigin
or in Kildare, in conformity with Cogitosus’ emphasis
upon the priority of the church in Kildare. Examination of the episodes given
in the time-frame of Cogitosus himself shows that he
was deeply involved in technical and practical matters concerning the monastery
in Kildare, of which he was most likely both prior and master craftsman. When
the Vita II episodes which are more detailed than the parallel Vita I
episodes are examined, it clearly emerges that the additions are all
appropriate to Cogitosus’ style of composition,
namely, enhancing his source with a combination of imagined technical details
and pious interpretations. This leads to the conclusion that Cogitosus based Vita II directly and solely on Vita
I. Finally consideration of Donatus’ account of
the Vita Brigitae by Animosus
suggests that Gregory’s Dialogues lib. I,7 inspired both of the names Cogitosus and Animosus as
pseudonyms for the author of Vita II. These results substantially
support the conclusion that Vita I was composed by Ailerán
of Clonard, and it is an abridgement of an earlier,
now lost, Vita by Ultán of Ardbraccan.
‘The
Chronology and Sources of the Early Irish Annals’, D. Mc Carthy, Early
Medieval Europe 10:3(2001), 323–41.
Abstract. Chronological divergence between the
different early Irish annals has hampered use of their many unique records of
events in
‘The
chronological apparatus of the Annals of Ulster AD 82–1019’, D.P. Mc Carthy, Peritia 16
(2002), 256–83.
Abstract. The view represented by Mac Airt and Mac
Niocaill in their 1983 edition of AU that the annals of ff. 12–14 of TCD 1282
are indeed part of the Annals of Ulster has recently been vindicated. Analysis
of the chronological apparatus of ff. 12–14 reveals that their author was
responsible for the introduction of Dionysiac epacts and continuous Anno Domini
into the Irish annals. He accomplished this by an extraordinary series of
interpolations into the pre-Palladian section of the Iona Chronicle that he
used as source, demonstrating both his computistical skill and profound
indifference to historical chronology. By AD 431 his apparatus was accurately
synchronised with all the Dionysiac chronological criteria, and he continued
with it, re-ordering many events through the fifth and sixth centuries. In the
seventh century he omitted a single kalend, which put all his subsequent
apparatus in arrears by one year. Collation of AU with the other annals
indicates that his compilation continued to c. 1019 and was completed shortly
after 1022. This compilation is identified with AU’s Liber Cuanach,
and Cuan hua Lothcháin (†1024) is proposed as the author.
The ante-Nicene Christian Pasch: De ratione paschali –
The Paschal tract of Anatolius, bishop of
Abstract. Very little contemporary evidence for the
diversity of Christian Paschal practice that preceded the Council of Niceae has survived. A unique exception, however, is the
Paschal tract of Anatolius, bishop of
‘Al-Khwarizmi’s
sine tables and a Western table with the Hindu norm of R=150’, D.P. Mc Carthy
& J.G. Byrne, Archive for the History
of Exact Sciences 57 (2003), 243–66.
Abstract. This paper demonstrates that the influential ninth
century astronomical tract of Ibn Musa al-Khwarizmi incorporated two sine
tables, one to norm R=150 at fifteen degree intervals reproduced from an Indian
source, and a second to norm R=60 at one degree intervals derived directly from
the chord table included by Ptolemy in his Almagest. Consequently it concludes
that the norm R=60 sine table preserved in the twelfth century Latin
translation of al-Khwarizmi by Adelard of Bath is
indeed the work of al-Khwarizmi, and is not an interpolation as recent scholarship
had maintained. An analysis of the one-second errors in the R=150 table
preserved in the Toledan tables shows that it was
derived by scaling and truncating an R=60 sine table, and the details suggest
this to be the work of al-Zarquali of Cordoba, and
that he used an edition of al-Battani’s sine table as his source.
‘On the
shape of the Insular tonsure’, D.P. Mc Carthy, Celtica xxiv (2003), 140–67.
Abstract. In 1639 bishop James Ussher reviewed all of
the evidence relating to the tonsure worn by clerics belonging to the British,
Scottish, Pictish and Irish churches from the fifth
to the ninth century, and concluded that it was semicircular
in shape. In 1703 the Benedictine scholar Mabillon, citing
only a portrait of uncertain provenance found in a St. Amand
manuscript proposed that the Insular tonsure consisted of entirely denuding of
hair the front part of the head, while the back was unshorn. Whilst Mabillon’s hypothesis was unsupported by any evidence and
in complete conflict with all of the sixth, seventh and eighth century
evidence, some coming from eye-witnesses, nevertheless it has largely prevailed
in modern times. This paper carefully reviews the early medieval evidence and
proposes that the tonsure was triangular in shape, resembling a Greek delta.
This hypothesis is tested against graphic portrayals of tonsures found in some
Insular Gospel texts and it emerges that texts associated with Columban monasteries, where the tonsure is known to have
been worn, do indeed confirm this triangular shape.
Encyclopaedia
entries ‘Annals’ and ‘Chronology of Irish history’ in B. Lalor
(ed.) The Encyclopaedia of Ireland, (Dublin 2003) pp. 33 and 193
respectively.
Abstract.
Brief accounts of the Irish annals and of the basis for the chronology of Irish
history.
‘The
emergence of Anno Domini’ in G. Jaritz & G.
Moreno-Riaño (edd.) Time
and Eternity – The Medieval
Discourse (Brepols: Turnhout,
2003), 31–53.
Abstract. Since at least the eighth century the system
of counting calendar years from the supposed year of the birth of Christ (ab
Anno Domini) has been attributed to Dionysius Exiguus, a Scythian monk in
‘The Original Compilation of the Annals
of
Abstract. Ever since 1861 when in his Manuscript Materials Eoghan O’Curry published James H. Todd’s opinion that the first
three folios of the TCD manuscript of the Annals
of Ulster (AU), i.e. TCD 1282 ff. 12–14, represented ‘a fragment of an
ancient copy of Tigernach’, the virtual consensus amongst scholars has been
that these folios were interpolated and hence that AU commenced at AD 431.
However this paper undertakes a critical examination of the paleographical
and codicological evidence and demonstrates that
these folios were in fact written by Ruaidhrí Ua Luinín, the principal scribe
of the MS, and they were bound to the following gatherings in the first
stitching of the codex. Furthermore their foliation by James Ware in the
earlier seventeenth century implies that there were then eleven folios
preceding f. 12, which itself commences at AD 82. This then implies that when
originally compiled TCD 1282 commenced either at or near Creation, as do the
closely related Annals of Boyle.
Moreover critical comparison of the annals transcribed by Ruaidhrí
Ua Caiside from TCD 1282 to
Rawlinson B. 489 ff. 1–32ra, with the numerous interpolations into
TCD 1282 in the hand identified as H2 in the edition of Mac Airt and
Mac Niocaill, shows this to be the hand of Ua Caiside and not
that of Cathal Mac Maghnusa
as has been repeatedly asserted. Finally, examination of the concluding folios
of TCD 1282, viz. ff 130r–143v,
shows that these were also written by Ua Caiside, as James Ware had asserted in 1639, and in them Ua Caiside developed a steadily
improving imitation of the hand of Ua Luinín. Hence the conclusion that this MS is complete at
the end and that it was written as far as 1504 by Ua Caiside in approximately that year.
‘Irish chronicles and their chronology’, the present edition online since 2005 at www.scss.tcd.ie/misc/kronos/chronology/synchronisms/annals-chron.htm
Abstract. This article provides a short introduction to the two important
chronological traditions employed in medieval Ireland. The earlier was the
kalend tradition, which was the original Annalistic chronological apparatus,
employing the kalends of January (1 January) to identify the commencement of
each successive chronicle year. The later was the regnal canon tradition, which
employed a table of the regnal years of the supposed successive kings ruling in
Ireland. The article provides links to a substantial account of the kalend
tradition and to the year-by-year synchronisation over AD 1–1590 of its best
witnesses, namely, the Annals of Tigernach, Chronicum Scotorum, the Annals of Roscrea, Ulster,
Inisfallen, Boyle, Connacht, Loch Cé,
and Mageoghagan’s Book (alias Annals of
Clonmacnoise). Links are also provided to a substantial account of the regnal
canon tradition, and to a parallel collation of the regnal years of its
significant witnesses; these include synchronisms, chronological poems, various
editions of Lebor Gabála, Michéal Ó
Clérigh’s Seanchas
Riogh Ereann and Annala
Rioghachta Eireann (alias
Annals of the Four Masters), Seathrún Céitinn’s Foras Feasa ar Éirinn,
and Ruaidhrí O’Flaherty’s Ogygia.
‘Chronological
Synchronisation of the Irish Annals’, the present edition online since 2005 at www.scss.tcd.ie/misc/kronos/chronology/synchronisms/Edition_4/K_trad/K_synch.htm
Abstract. This article briefly outlines
the early use of the kalends of January to sequence a chronicle by Rufinus of Aquiliea (†410), and
its subsequent continuation in Iona, Clonmacnoise, Armagh, Derry, and along the
river Shannon. It provides an extensive discussion of the significant features
of the principal collated sources, namely, the Annals of Tigernach, Chronicum Scotorum, the
Annals of Ulster, Inisfallen, and Mageoghagan’s
Book (alias Annals of Clonmacnoise), and brief discussions of the Annals of
Boyle, Roscrea, the Fragmentary Annals, Bede’s Chronica maiora, and the Annales Cambriae. It examines the problem of
seven kalends missing at AD 425–431, and a further six kalends missing over AD
612–664, and proposes a restoration of these. From this is derived the
synchronised chronology from them over AD 1–1590 based upon the chronological
criteria of the Annals of Tigernach, Chronicum Scotorum, and the Annals of Ulster, Connacht, and Loch Cé. Over AD 1–1590 tokens of the annalistic entries are
collated in parallel, sometimes comprehensively, at other times using sampling.
A chronological survey of Michéal Ó Clérigh’s Annals of the Four Masters is presented
demonstrating that its chronology is chaotic relative to all of the older
annalistic sources, and for this reason it has not been included in the
collation.
‘Collation
of the Irish regnal canon’, the present edition online since 2005 at: www.scss.tcd.ie/misc/kronos/chronology/synchronisms/Edition_4/RC_trad/RC_collation.htm
Abstract. This article describes the ten principal witnesses to the regnal canon, namely the Laud synchronisms, chronological poems by Flann Mainistreach, Gilla Cóemáin and Gilla mo Dubda Ó Casaide, various editions of Lebor Gabála, Michéal Ó Clérigh’s Seanchas Riogh Ereann and Annala Rioghachta Eireann (alias Annals of the Four Masters), Seathrún Céitinn’s Foras Feasa ar Éirinn, and Ruaidhrí O’Flaherty’s Ogygia. It describes and provides a parallel collation of these regnal years for each reign, and discusses their significant correspondences and differences. Where possible it identifies the location chosen by each source for the year of the Incarnation.
The Irish Annals: Their genesis, evolution and history, Four
Courts Press, (Dublin & Portland, OR, 2008), xvi + 416 pages with illustrations.
This is the first book to systematically survey
the manuscripts of the Irish Annals, the unique mediaeval Christian chronicles
which were maintained in
Review of Thomas M. Charles-Edwards The
Chronicle of
‘Bede’s primary source for the Vulgate chronology in his chronicles in De temporibus and De temporum ratione’, in Immo Warntjes and Dáibhí Ó Cróinín (edd) Computus and its cultural context in the Latin West – Proceedings of the 1st International conference on the Science of Computus in Ireland and Europe, Galway, 14–16 July, 2006 (Brepols, Turnhout 2010), 159–89.
Abstract. Mommsen’s 1898 assumption that Bede had compiled the
Vulgate chronology of his chronicles in De
temporibus (DT) and De temporum ratione
(DTR) has been simply reiterated by scholars ever since. But critical
collation of Bede’s chronicles with the Irish Annals leads to the conclusion
that their common features, including their Vulgate chronology, derive from a
common source that originated in a chronicle compiled by Rufinus
of Aquileia †410. By the year 538 Rufinus’ chronicle
was being continued in
A review of Nicholas Evans, The Present and Past the in medieval Irish chronicles (Boydell Press, Woodbridge, Suffolk 2010), pp. xv + 289, published by The Medieval Review and available online at:
https://scholarworks.iu.edu/dspace/bitstream/handle/2022/9494/10.10.04.html?sequence=1
‘The
study and use of numbers in early Irish monasteries’, chapter thirteen in
Charles Doherty, Linda Doran, and Mary Kelly (edd) Glendalough: City of God (Four Courts Press, Dublin, 2011),
223–37.
Abstract. The presence in the manuscripts of
early Christian Ireland of sophisticated geometrical constructions, complex numerical
structures embedded within texts, and computistical works discussing the
different computations of the date of Easter, all attest to a refined interest
and capability in numbers and their uses in early Irish monasteries. The Latercus, compiled in circa 410 by
Sulpicius Severus in southern Gaul, is the earliest of these Paschal traditions
known in
‘A facsimile edition of the Annals of Roscrea’,
Bart Jaski & Daniel Mc Carthy available online at
www.scss.tcd.ie/misc/kronos/editions/AR_portal.htm
Abstract.
The Irish chronicle known to modern scholarship as the ‘Annals of Roscrea’ is
found only in the manuscript
The Annals of Roscrea – A diplomatic edition, Bart Jaski &
Daniel Mc Carthy, (Roscrea People: Roscrea, Co.
Abstract. The Irish chronicle known to
modern scholarship as the ‘Annals of Roscrea’ is found only in the manuscript
This edition is based upon the online edition,
‘A facsimile edition of the Annals of Roscrea’, see above, and it was published
in a limited edition of seventy-five copies with the generous assistance of the
Roscrea People, Roscrea Heritage Society, and George Cunningham of Parkmore,
Roscrea.
‘On the arrival of the Latercus in
Abstract. The hypotheses published in 1733 by van der Hagen regarding the supposed
computistical parameters and Roman origin of the Latercus, the
84-year Paschal tradition followed by the early Insular churches, and the
alleged forged status of Paschal tracts cited by Insular authors are profoundly
mistaken when viewed beside the evidence of the copy of the Latercus discovered by Dáibhí Ó Cróinín in Padua MS I
27. Furthermore, the computistical features of this
‘Ruaidhrí Ó Casaide’s contribution to the Annals of Ulster’ in Seán Duffy (ed.) Princes, Prelates and Poets in Medieval Ireland - Essays in honour of Katharine Simms (Dublin: Four Courts Press, 2013), 444-59.
Abstract. Ruaidhrí Ó Casaide, †1541, a member of a Fermanagh medical family and vicar of Clogher, made three major scribal contributions to the compilatiion of the two principal manuscripts of the Annals of Ulster, Trinity College, Dublin, MS 1282 (MS H), and Oxford, Bodleian, Rawl. B. 489 (MS R). Namely, he wrote numerous marginal and interlinear additions to MS H, he wrote the years AD 1489–1504 in concluding folios 130r–143v of MS H, and he transcribed from MS H the years AD 431–952 in folios 1–32r of MS R. However, a comprehensive survey of the occurrence of Arabic numerals, alternative entries with contrasting chronology, and temporal emphatics such as ‘hoc anno’ and ‘in bliadhain-si’, discloses that Ó Casaide was also the editor of the exemplar used by Ó Luinín to write folios 12–130r of MS H. Consideration of the various temporal horizons in MS H and MS R shows that MS H was written by Ó Luinín and Ó Casaide between circa 1495–1505, while MS H was transcribed to MS R by Ó Casaide and Ó Luinín in circa 1505–7, and the entries were then continued by Ó Casaide until his death in 1541, the additional entries being written for him by twelve different amanuenses.
‘TCD MS 1282 (The Annals of Ulster): a scholar’s
book and exemplar’, in W.E. Vaughan (ed.) The Old Library -
Abstract. A short essay reviewing the contributions of both Ruaidhrí Ó Casaide and Ruaidhrí Ó Luinín to the writing and compilation of the two principal manuscripts of the Annals of Ulster, namely Trinity College, Dublin, MS 1282 (MS H), and Oxford, Bodleian, Rawl. B. 489 (MS R). This shows that when transcribing MS H into MS R Ó Casaide introduced textual and orthographical changes to the entries. A summary account is also given of the publication of various editions of these annals, starting with Rev. Charles O’Connor in 1826, through to the edition of Seán Mac Airt and Gearóid Mac Niocaill in 1983.
‘The illustration and text on the Book of Kells folio 114rv’, Studies in
Iconography 35 (2014), 1 38.
Abstract. This paper presents the evidence that the illustration
on folio 114r of the Book of Kells showing two similar figures flanking Jesus,
and supporting his arms, represents the disciples James and John watching with
him during his Agony in the
It is further shown that this is one of a
number of instances in the Book of Kells where warmth is expressed towards
John, and ambivalence towards Peter, an attitude found in the Paschal tract De ratione paschali which provided the authority to the early
Insular churches for celebrating Easter on luna fourteen. Moreover, it is shown
that on folio 32v Jesus is portrayed with the triangular Insular tonsure
imposed. These heterodox identifications rule out as possible provenances for
the Book of Kells all those Insular churches that had adopted the Paschal and tonsurial traditions followed by the Roman church, which
rejected luna fourteen and prescribed the coronal tonsure. This effectively
leaves only Kells, whose foundation is described in the Annals at 807 as ‘the
new monastery of Colum Cille’, as the only plausible
location for the compilation of the Book. The magnificence of the Book suggests
that it was commissioned for the church of this new monastery at Kells, which
was completed in 814.
‘Dalkey Quarry Tramway 1815-c.1855’, in David
Gwynn (ed.), Early Railways 5, (Clare,
The book is a selection of the
papers presented at the Fifth International Early Railways conference in
Carnarvon,
Abstract. An account of the horse-drawn
tramway and funicular system constructed 1816–17 at the instigation of the
Scottish engineer, John Rennie, to transport granite from the quarry at Dalkey,
county Dublin, to face the piers for the harbour designed by Rennie at Dún
Laoghaire, about two miles away. The tramway was very robustly designed and
constructed, and continued in service until the middle of the nineteenth century.
‘The contribution of Armagh scholarship to the Annals of Ulster’, Seanchas Ard Mhacha, 25 (2014), 63–83.
Abstract. This paper examines specifically the
contributions of
‘The Chronology of Saint Columba's Life’, in Pádraic Moran & Immo Warntjes (eds), Early Medieval
Abstract. Between Adomnán’s
Vita Columbae
and Bede’s account in his Historia Ecclesiastica, Saint Columba’s life and missionary
career are the best recorded of all early Irish ecclesiastics. Further, and in
great contrast to his fifth-century British missionary predecessor, Saint
Patrick, Columba’s chronology has not been the subject of controversy in modern
times. At least from the seventeenth century scholarship has been almost
unanimous that Columba died in 597, a date that derives from Adomnán’s assertion that he died on Sunday, and that he
left
‘On reconstructing medieval Irish chronicles’,
by D.P. Mc Carthy – unpublished.
Exposition. In 2013 the journal Early Medieval Europe published Roy Flechner’s article, ‘The Chronicle of Ireland: then and
now’, in which he endorsed Kathleen Hughes’ 1972 hypothesis of a ‘Chronicle of
Ireland’, and added a number of his own hypotheses. In this he found it
necessary to reiterate and approve dismissive criticism of my own published
analysis of the origin and evolution of the Irish Annals. As I considered that
both Hughes’ and Flechner’s hypotheses rest upon
mistaken assumptions and that I was entitled to a right of reply to his
criticism, I submitted an article entitled ‘On reconstructing medieval Irish
chronicles’ to Early Medieval Europe on
27 August, 2015. On 26 November, 2015, the Editors notified me by email that
Reviewer 1 disputed my right of reply, with which view they concurred, and so
they rejected my submission. Here is the link for the pdf of my submission of ‘On
reconstructing medieval Irish chronicles’. A postscript is suffixed to this
submission dated 6 July, 2016, which reproduces the Editors’ email, including
the Reviewers’ ‘Comments to the Author’, so that scholars may judge the
situation for themselves.
Abstract. Examination of Kathleen Hughes’ 1972
hypothesis of a ‘Chronicle of Ireland’ reveals that her primary assumption that
the Annals of Ulster represent ‘the most complete version of the Irish annals’
was mistaken. This assumption has strongly influenced the understanding of
early Irish annals by most subsequent scholarship. However, this article
contends that the kalend and ferial structure of the Clonmacnoise group of
annals embodies the earliest surviving witness to the early annals. The
methodology of Roy Flechner’s recent analysis of the
compilation, motivation, and classification of the ‘Chronicle of Ireland’ is
also examined and found to be misjudged.
‘Offprints of Ada Lovelace’s translation of Luigi Menabrea’s account of Charles Babbage’s Analytical Engine, incorporating an offprint by Babbage’, by D.P. Mc Carthy – unpublished.
Exposition. This paper was submitted to the IEEE Annals of the History of Computing on 14 September 2016. On 31 October 2016 an
email from the Chief Editor, Dr Nathan Ensmenger, included two reviews, the first recommending
publication and the second recommending rejection. Dr
Ensmenger concurred with the second reviewer so that
the article was not published. Here is the link to a pdf of my submission Offprints_of_Ada_Lovelace’s_translation. In this pdf a
postscript has been suffixed to the submission reproducing Dr
Ensmenger’s email, including the two reviews, so that
scholars may judge the situation for themselves.
Abstract. This article examines textual and bibliographical
aspects of Ada Lovelace’s article translating and annotating Luigi Menabrea’s
account of Charles Babbage’s Analytical Engine, published in the Scientific Memoirs of 1843. Textually it
concludes that the preface to her translation, although apparently attributed
to the ‘Editor’, was actually compiled by Babbage himself, and in it he
reviewed the history of both his Difference Engine and Analytical Engine.
However, as published the account of the Analytical Engine is incomplete
because the concluding section dealing with Babbage’s conflict with the British
Government was refused by the editor of the Scientific
Memoirs. Consequently, Babbage published this concluding section soon
afterwards in the Philosophical Magazine
of 1843. For the remainder of his life Babbage regarded this publication as his
‘defense’, and he placed it first in his un-published
‘History of the Analytical Engine’. Bibliographically it is shown that
offprints of both publications circulated amongst friends and contemporaries of
both
‘Analysing and Restoring the Chronology of the Irish Annals’, in Ralph
Kenna, Máirín MacCarron
& Pádraig MacCarron (eds),
Maths Meets Myths: Quantitative Approaches to Ancient Narratives,
(Switzerland: Springer International Publishing, 2017), 177–194.
Abstract. Substantial annalistic chronicles
of Irish affairs exist in a number of medieval versions, but they exhibit
considerable variation both in the sequences of events and the chronological
apparatus used to link each year to the Julian calendar. Of these, the Anno
Domini years of the Annals of Ulster have been principally relied upon by
historians. However, these are demonstrably incorrect from the seventh to the
eleventh centuries. Moreover, its remaining chronological data of ferials and
lunar epacts at the kalends of January, that is, the day of the week and the
age of the moon on 1 January, are almost all interpolations by a later scribe.
On the other hand, the Annals of Tigernach and the Chronicum
Scotorum have only kalends and ferials marking the
commencement of each year from the Incarnation up until the mid-seventh
century. Because these kalends and ferials are susceptible to scribal
miscopying they were dismissed by historians and textual scholars as
“hopelessly confused”. However, analysis of the 28 year cycle of the ferials
reveals that they possess a powerful error-correction property. Exploitation of
this property has enabled the restoration of all the missing kalends and
erroneous ferials of the Annals of Tigernach and Chronicum
Scotorum, as well as of the closely related Annals of
Roscrea, known collectively as the Clonmacnoise group. Using computer table
structures, the kalends and ferials and events of these three have been
synchronized with the Anno Domini years over the range AD 1–1178, and this
tabulation, with cross-references to the other Irish medieval annals, has been
made available online at www.irish-annals.cs.tcd.ie.
In this chapter the process of analysis, correction, and synchronization is
illustrated, taking the year of the death of St Patrick as an example.
‘Representations of tonsure in the Book of Kells’, Studia Celtica 51 (2017), 89–103.
Abstract Four Insular documents from the
seventh and eighth centuries show that a major controversy took place amongst
the Insular churches regarding the shape of the tonsure worn by clerics. Those
who followed the customs of the Roman church wore a coronal tonsures, oval or
circular in plan, while those belonging to some earlier Irish and British churches
wore a delta tonsure, triangular in plan. This paper critically examines six
figures in the Book of Kells proposed to have been illustrated with tonsures.
Three of these at ff. 32v, 34r and 273r all show Jesus with the delta tonsure.
The haloed figure above the second Canon table at f. 2v is likewise shown with
the delta tonsure. On the other hand, the mounted figure at f. 255v is shown
with a coronal tonsure and is explicitly coupled to the words ‘unum’ and ‘peccauerat’ of Luke
17:1 and 17:3 respectively. In Luke 17:1–3 Jesus censures all those who give
cause for temptation to sin, saying it would be better that they were cast into
the sea with a mill-stone about their neck. Consequently, by this graphic
presentation of the coronal tonsure the compilers of Kells expressed their
strong disapproval of it. A sixth figure at f. 182r proposed by James McIlwain in 2008 to be illustrated with the coronal tonsure
is shown in fact to represent Pontius Pilate wearing an oval cap. Thus the five
illustrations of tonsure in the Book of Kells represent a graphic polemic,
exalting those who wore the delta tonsure, but directed against those who wore
the Roman coronal tonsure.
‘The Paschal cycle of St Patrick’ in Immo Warntjes & Dáibhí Ó Cróinín (edd) Late Antique Calendrical Thought in the
Early Middle Ages – Proceedings of the 3rd International Conference
on the Science of Computus in Ireland and Europe – Galway, 16–18 July, 2010
(Brepols: Turnhout, 2017), 94–137.
Abstract. Notwithstanding the substantial
corpus of early mediaeval references to St Patrick and his works, the only
account we have of a paschal cycle associated with him is that provided by
Cummian in his letter to Ségéne of Iona and Bécán the
hermit in c. AD 633. In this letter
Cummian identified himself and his community with Patrick, but he furnished
only limited technical details for both Patrick’s cycle and the cycle he
indicated that he and his community had recently adopted. However, critical
examination of Cummian’s account shows that Patrick had adapted the 532-year
paschal cycle compiled by Victorius of Aquitaine in AD 457, and that this was
the cycle that Cummian’s community and other influential southern Irish
churches had resolved to adopt at the synod of Mag Léne
in c. AD 630. Consequently, Cummian’s account of Patrick’s cycle, the earliest
attested reference to him, holds significant implications for both the
chronology of Patrick’s mission to
‘Recovering years lost from the
Irish annals’, in Joe Fenwick (ed.), Lost
and Found III – Rediscovering more of
Abstract. This article gives an account for a
general audience of the two Irish annals employing the same sequencing
mechanism as the
‘The Genesis and Evolution of the Irish Annals to AD 1000’, Frühmittelalterliche Studien 52
(2018), 119–155.
Abstract. The ten major compilations of Irish
Annals collectively present thousands of entries from Creation to AD 1616.
These are preserved in manuscripts from the eleventh to the seventeenth
centuries and, with virtually no contemporaneous documentation on their
compilation, they pose a complex challenge to deduce their origin and
evolution. Mac Neill published the first hypothesis in 1913, and this was
further developed by O’Rahilly in 1946. In 1972 Hughes essentially reiterated O’Rahilly’s hypothesis, entitling it the ‘Chronicle of
Ireland’, which she envisaged as a recompilation of earlier Irish regional
annals in c. 913. Since then her hypothesis has been endorsed and developed by
other scholars from
‘The Council of Nicaea and the Celebration of the Christian Pasch’, in
Kim, Young Richard (ed.), The Cambridge Companion to the Council of Nicaea,
(Cambridge University Press: Cambridge, 2021), 242 – 275.
Abstract. In 525 Dionysius Exiguus in Rome
compiled his 95-year continuation of the Alexandrian Paschal table and this
table came eventually to schedule the celebration of Pasch for the entire
western Church. In an accompanying letter Dionysius stated that the Council of
Nicaea had authorized the 19-year cycle of Paschal full moons of the
Alexandrian table, and that this cycle had been subsequently maintained by the
Alexandrian bishops Athanasius († 373), Theophilus († 412), and Cyril († 444).
These statements were accepted and reiterated for almost twelve centuries until
1718 when Johann Wilhelm Jan challenged them. Since then some scholars have
endorsed Jan’s conclusion, while others have disputed the matter and insisted
that some element of Nicaean authority indeed lies behind the Alexandrian
Paschal table. This article re-examines the matter by first considering the
Evangelistic authority for the celebration of Pasch and showing that while the
Synoptic Gospels agree that the Crucifixion took place on the day after the
Jewish Passover, John’s Gospel places it on the day of the Passover and hence
on the fourteenth day of the spring moon. Thus there is serious chronological conflict
inherent in the Evangelistic accounts of Jesus’ Crucifixion. At Nicaea the
emperor Constantine sought to resolve this conflict and all the contemporaneous
accounts agree that by a substantial majority the Council decreed that
celebration of Pasch be allowed only on Sunday, and that celebration on the
fourteenth day of the moon was to be rejected. There is no contemporaneous
evidence that the Council’s decision went beyond this. Nevertheless, scholars
who have believed that the Alexandrian Paschal table derived from Anatolius’
19-year Paschal table compiled in the mid-third century have preferred to
assume that an Alexandrian continuation of this cycle was in some way endorsed
by the Council. However, this paper presents the argument that in fact the origin
of the Alexandrian Paschal table lies rather with bishop Theophilus in the last
decades of the fourth century, about sixty years after the Council of Nicaea.
Consequently, Dionysius’ claim that Athanasius had maintained a 19-year cycle
of Paschal moons authorized by the Council of Nicaea is unsustainable.
‘Tonsure’, The Brill Encyclopedia of Early Christianity Online, dated 22 Sept. 2022, at: https://referenceworks.brillonline.com/browse/brill-encyclopedia-of-early-christianity-online.
Abstract. In
the context of Christianity tonsure refers to the practice of clerics cutting
their hair according to a style adopted by their ecclesiastical institution.
This short article reviews the tonsure practices adopted by the Eastern and
Western churches and concludes that the Eastern churches only required that
ecclesiastics keep their hair cut short in accordance with the apostle Paul’s
stricture in 1 Corinthians 11:3–16. On the other hand, by the early
sixth century the Roman church had adopted a coronal tonsure with a disc of the
crown of the head kept trimmed to the scalp, associating this retrospectively
with Saint Peter, and this coronal tonsure eventually prevailed in the Western
churches. However, prior to this, in the fifth century, a triangular tonsure in
the shape of a Greek delta ‘Δ’ on the crown of the head was introduced
most likely by Sulpicius Severus in southern Gaul. From the fifth to at least
the ninth century certain monks and clerics in Britain and Ireland, who
considered John the pre-eminent disciple, insisted on this delta tonsure.
Eventually, however, antagonism and opposition from proponents of the coronal
tonsure succeeded in eliminating the delta tonsure.
‘Sulpicius
Severus’s construction of his 84-year Paschal table’, D. Mc
Carthy, Peritia 33 (2022), 139–58.
Abstract. The structure and termini of the 84-year Paschal
table with a 14-year saltus followed by the early mediaeval churches of Britain
and Ireland remained a matter of conjecture until 1985, when Dáibhí Ó Cróinín identified a full copy of the table in MS
Padua, Biblioteca Antoniana,
I.27. This article undertakes a detailed analysis of
the structure of the Padua table and demonstrates that its achievement of the
Paschal termini of luna 14–20 between 26 March and 23
April of Anatolius’ De ratione paschali
resulted from Sulpicius Severus’ skilful exploitation of the synchronism
between his 14-year saltus and the 28-year solar cycle. While precisely
maintaining Anatolius’ Paschal termini Sulpicius’ table achieved both close
synchronism with the real moon and, when projected back to AD 29, the Paschal
criteria of Sunday 27 March, luna 17. These criteria corresponded with the
belief that prevailed in the Latin world of late Antiquity that Jesus had been
crucified on Friday, 25 March, luna 15, and had
resurrected on Sunday, 27 March, AD 29.
‘The Zeitz Paschal Table of AD 447’, D. Mc
Carthy in I. Warntjes, T. Loevenich and D. Ó Cróinín
(edd.), Pre-Carolingian Latin Computus and its
Regional Contexts (Brepols: Turnhout, 2023), 17–85.
Abstract.
In
1816 Andreas Cramer identified that the two bifolia in late antique Latin
script lining the covers of MS Zeitz Stiftsbibliothek
fol. 33, preserved fragments of a Paschal table and its associated preface and
in 1826 he published a transcription of all the legible text. The preface fragment
showed that the table had been compiled in AD 447 and it commenced in AD 29 and
employed an 84-year lunar table, all suggestive of a Roman context. In the
ensuing century Gustav Hänel, Theodor Mommsen, and
Bruno Krusch published increasingly accurate editions of the preface and table
fragments. However, a major obstacle to reconstruction of the Paschal table was
that the available preface provided no indication of the compiler’s Paschal
principles, the termini to be imposed
on the Julian calendar date of Pasch and age of the Paschal moon. Remarkably,
in 2005 three further small fragments were identified in Zeitz which were
published by Eef Overgaauw
and Frank-Joachim Stewing, and these revealed
that the compiler intended to tabulate Paschal dates and moons according to
both Roman and Alexandrian termini.
This article provides a full transcription of all the known manuscript
fragments, a reconstruction of the Paschal table based upon these, and a
discussion of the historical context of the table’s compilation.
Page updated 3 May 2024