Tighearnach ua Cleirigh
Tighearnach ua Cleirigh (died 916) was King of Uí Fiachrach Aidhne. "Sub anno" 916, the Annals of the Four Masters states " Tighearnach ua Cleirigh, lord of Aidhne, died." He appears to have been a son of the previous king, Maelfabhaill mac Cleireach. His appellation was therefore not a surname, merely denoting he was the grandson of Cleireach. However, his descendants adopted the surname Ó Cléirigh, and all subsequent bearers of the name are believed to descend from him. Notables include: