Tomas Ó Con Ceanainn
Encyclopedia
Overview
Sub anno 1478, the Annals of the Four MastersAnnals of the Four Masters
The Annals of the Kingdom of Ireland or the Annals of the Four Masters are a chronicle of medieval Irish history...
state that
Thomas O'Concannon, Lord of Hy-Diarmada, was slain by the son of his own brother"
He was succeeded by William, who died later the same year.