DIARMAIT MAC CERBAILL
times—messages that frequently dealt with the ten-
sions between church and state. Possibly the earliest
writer to adapt Diarmait to his own ends was St. Colum
Cille’s biographer, Adomnán, writing at Iona around
700, who claimed that Diarmait was totius Scotiae
regnatorem Deo auctore ordinatum (ordained by God
as ruler of all Ireland).
There is no indication as to when, or where, Diarmait
was born. The genealogical tradition recounts that
Diarmait was a son of Fergus Cerrbél and grandson of
Conall Cremthainne, son of Niall Noígiallach. The
Banshenchas claims that his mother was Corbach,
daughter of Maine of the Laigin. Diarmait was pur-
portedly married to Mugain, of the Eóganachta of
Munster, and to Muirenn Máel, of the Partraige of
Connacht. The rivalry between these two women is
recounted in a tenth-century text Geinemain Áedha
Sláine(the conception of Áed Sláine). According to
theGeinemain, Mugain, who had been made barren by
God because of her hostility to Muirenn, was blessed
by St. Finnian of Moville (presumably an error for
Finnian of Clonard), in consequence of which she
became pregnant with Áed Sláine. Diarmait is said to
have had two additional wives, both from Conmaicne
in Connacht: Eithne, who was mother of Colmán Már,
and Brea, mother of Colmán Bec. The twelfth-century
Accalam na Senórachalone mentions another wife of
Diarmait: Bé Binn from Scotland.
Diarmait became king of Tara in 545 following the
death of Tuathal Máelgarb, said to have been a grand-
son of Coirpre, son of Niall Noígiallach. According to
later legend, shortly before his accession to the king-
ship, Diarmait was in hiding from Tuathal at Clon-
macnoise and assisted St. Ciarán in the building of the
first church at that foundation (a tradition that is also
recorded on a panel of the early tenth-century Cross
of the Scripturesat Clonmacnoise). On this occasion,
Ciarán predicted that Diarmait would be “king of Ire-
land” on the following day, and this came to pass when
Tuathal Máelgarb was killed that night. This legend
presumably owes its origins to a period, before the
tenth century, when the relationship between Clonmac-
noise and the Clann Cholmáin was especially close.
Weknow that the mid-ninth-century was such a period:
Ruaidrí mac Donnchada, who died in 838, was tánaise
abb(i.e., designated to succeed as abbot) of both Clon-
macnoise and Clonard, and was abbot of other, unspec-
ified, churches. He was a son of Donnchad Midi, the
Clann Cholmáin over king of the Uí Néill. The tale
Aided Diarmata(the violent death of Diarmait),
reveals a more strained relationship between Clann
Cholmáin and Clonmacnoise. It recounts how Ciarán,
angry at the fact that Diarmait had slain an enemy of
his, one Flann, on lands that he had just given to the
Saint, declared that Diarmait would suffer the same
triple death as Flann, namely, through wounding,
drowning, and burning.
In 558 or 560 (the annals give both dates), Diarmait
celebrated the Feis Temro. Some of the collections of
annals state that this was the last celebration of the
Feis. The Feis Temrowas a celebration held once
during the reign of a king, and was, according to
D.A.Binchy “a pagan fertility rite, with a quasi-divine
king at its centre.”
Later legend explained the abandonment of Tara as
follows. Diarmait had violated the sanctuary given by
St. Ruadán of Lorrha to Áed Guaire, the king of Uí
Maine in Connacht, when he seized Áed and took him
prisoner to Tara. Ruadán, supported by St. Brendan,
went to Tara to demand the release of Áed and fasted
against the king to force his hand. Ruadán also placed
a curse on Tara so that it would henceforth remain
deserted. The king, finally recognizing the superior
power of the clergy, relented and agreed to release Áed.
This tale may date from as late as the eleventh century,
when the issue of sanctuary rights bedeviled the rela-
tionship between Church and State.
In contrast to the positive light in which Adomnán
portrayed Diarmait, the annals recount that a dispute
between Diarmait and Colum Cille (the precise nature
of which is unclear) was the cause of the battle of Cúil
Dreimne (near Benbulben in County Sligo) in 561,
when an army comprising the Cenél nEógain, Cenél
Conaill, and the Connachta, which, reputedly, had the
full support of Colum Cille, routed Diarmait. Diarmait,
however, is said to have relied on the support of the
Druids.
Diarmait was defeated at Cúil Uinsen in Tethbae
(approximately equivalent to modern County Long-
ford) by Áed mac Brennáin, the king of Tethbae, in
562 or 563, and he fled from the battlefield.
Diarmait was killed (allegedly at Mag Line, in
County Antrim) in 564 or 571 by Áed Dub mac Suibni,
of the Cruithni, who was said to have been his former
foster child. The Aided Diarmata relates that Diarmait’s
demise took the form of the “triple death” foretold
previously. Áed Dub’s responsibility for Diarmait’s
death may be historically based, as he is condemned
by Adomnán for this deed. Some of the annals recount
that Diarmait’s head was buried at Clonmacnoise,
while his body was buried at Connor (Co. Antrim).
PAUL BYRNEReferences and Further Reading
Anderson, A. O., and M. O. Anderson, eds. Adomnan’s Life of
Columba. Edinburgh: Nelson, 1961.
Binchy, D. A. “The Fair of Tailtiu and the Feast of Tara.” Ériu
18 (1958): 113–138.
Byrne, Francis John. Irish Kings and High-Kings. London:
Batsford, 1973.