He was responsible for the compilation of the Fragmentary Annals of Ireland, which he wrote on a vellum manuscript. In 1643, they were copied for Rev. John Lynch of Galway by Dubhaltach Mac Fhirbhisigh. The original manuscript is now lost but a copy survives of Mac Fhirbhisigh's text. The manuscript (MS. 7, c. n. 17) is incomplete and includes five fragments of annals beginning in 573 and ending in 914.
