Prince Fiachra, brother of Niall of the Hostages, was twelve years King of Connaught. After the death of his brother Brian, he was appointed to command the army of Niall, the supreme monarch. It was while holding this high official position that Prince Fiachra marched into Munster, and at the battle of Kenry defeated the Munster forces, and exacted hostages for the future allegiance of the Kings of Munster to
Niall. But through the treachery of the hostages he failed to reach Tara. They succeeded in seizing him, and having him buried alive at Hy Mac Uais, the present barony of Moy Goish in Westmeath. So died Fiachra of " the Flowing Hair," the ancestor of the tribes of Hy Fiachrach Aidhne, leaving live sons, the youngest but most distinguished of whom was Dathy.212