See The Mairtine for early Irish beginnings. Later surname variations include Mac Giolla Mhártain, Ó Maol Mhartain, Ó Martain, Ó Máirtín, Mac Máirtín, Mac Máel Martain and were probably distantly related from a Keltoid root stock. Recent DNA evidence has
this group in Ireland for 3000 years and aligning with the Ulaidh, Errain, and Eóghanacht in Munster and later in the DalRiata kinship groups.
Echmílid mac Máel Martain was Bishop of Down to 1202. Giolla Ernain Ó Martain, who died in 1218, was an Irish poet and Chief Ollam of Ireland. Fearghal Ó Martain, O.E.S.A., was Bishop of Killala from 1425 to 1432.
After the Norman invasion of Ireland in 1169, numerous new, unrelated bearers of the name from Britain and France, settled in Ireland.
The most well-known Norman family in County Galway were the Martyn family, who were counted among The 13 Tribes of Galway.