Martyrology of Donegal

Mícheál Ó Cléirigh (c. 1590 – 1643), sometimes known as Michael O'Clery, was an Irish chronicler, scribe and antiquary and chief author of the Annals of the Four Masters, assisted by Cú Choigcríche Ó Cléirigh, Fearfeasa Ó Maol Chonaire, and Peregrinus Ó Duibhgeannain.

Grandson of Tuathal Ó Cléirigh, a chief of the sept of Uí Chléirigh in Donegal, he was born in Kilbarron near Creevy, between Rossnowlagh and Ballyshannon on Donegal Bay. He was baptised Tadhg Ó Cléirigh and was known by the nickname Tadhg an tSléibhe (meaning Tadhg of the mountain), but took the name of Mícheál when he became a Franciscan friar. He was the youngest of four sons of Donnchadh Ó Cléirigh and his mother was Onóra Ultach. Of his older brothers were Uilliam, Conaire and Maolmhuire, Conaire is known to have worked on the annals as a scribe, while Maolmhuire also became a Franciscan at Louvain. Micheál was a cousin of Lughaidh Ó Cléirigh (fl. 1595–1630), also famous as an Irish historian and author of one of the major sources of the annals.

As a member of one of the foremost learned families of Gaelic Ireland, Ó Cléirigh received a wide-ranging and thorough education. He records that he was taught, for instance, by a Baothghalach Ruadh Mac Aodhagáin, an individual who may have been active in County Tipperary. Tadhg followed Maolmhuire to continental Europe some time after the Flight of the Earls. He may be the Don Tadeo Cleri who was serving as a soldier in Spain in July 1621. At some point before March 1623 he became a lay brother of the Franciscan order. He was never ordained a priest.

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