Dictionary of National Biography, 1885-1900/Niall (d.1139)
NIALL (d. 1139), anti-primate of Armagh, was son of Aedh and grandson of Maelisa, who with his father, Amhalghaidh, filled the primacy of Ulster for fifty-six years. Another member of his family held the temporalities of the see for three years after the election of St. Malachy O'Morgair [q. v.], and in 1131 they were seized by Niall, who publicly displayed the Bachall Isa, or pastoral staff of Jesus, to the populace, and was able for a short time to hold his own. He also seized an ancient book, probably that now known as the book of Armagh. St. Bernard, the friend of his rival, speaks of him with severity as ‘Nigellus quidam, imo vero nigerrimus.’ He wandered about in the diocese, and reasserted his claim in 1137, when Giolla Iosa succeeded Malachy as the regular archbishop, but was driven out and died, ‘after intense penance,’ say the chronicles, in 1139.
[Annala Rioghachta Eireann, ed. O'Donovan, ii. 1063; Colgan's Trias Thaumaturga, 1650, p. 305; Bernardi Opera, Paris, 1586, ii. 724–725; Stuart's Historical Memoirs of the City of Armagh, Newry, 1819.]