Note 450 — Chapter III · THE CONQUEST OF IRELAND. 795–1172.
Reading edition
Four Masters, a. 1167 (O’Donovan, vol. ii. pp. 1165–1167). Among the slain they mention “the son of the king of Britain, who was the battle-prop of the island of Britain, who had come across the sea in the army of Mac Murchadha.” This can only mean a son or brother of Rees; but neither Gerald nor the Welsh chronicles make any mention of such a person in Ireland.