Michael O’Clery led a team who compiled the Annals of the Kingdom of Ireland (more commonly known as the Annals of the Four Masters), a comprehensive history of Ireland. The team included his cousin Cucogry O’Clery, Fearfasa O’Mulconry and Cucogry O’Dugan (historians), his older brother Conary and Morris O’Mulconry (both copyists). They made two handwritten copies between 1632 and 1636 at a Franciscan friary on the River Drowes dividing Leitrim and Donegal. The work remained inaccessible until English translations were published in the 1840s.
Michael, a learned poet and antiquary, may have aspired to become the O’Donnell historian. Their downfall forced him to leave Ireland to seek a better life. He may have served as a soldier in the Spanish Netherlands (along with many other Irishmen) before joining the Irish Franciscans as a lay brother c. 1623 at St Anthony’s College, Louvain. His superiors wanted the Annals to ‘document the origins and history of the Catholic kingdom of Ireland’, historian Bernadette Cunningham observed. That parts of its more than 400,000 words of text contain ‘a certain political bias’, Cunningham noted, was because the O’Clerys ‘were merely following a time-honoured tradition within their family by eulogising the achievements of the leaders of the O’Donnells’.