Muirchertach Ua Carmacáin, Bishop of Clonfert, 1195-1203.
Ó Cormacáin was a member of an ecclesiastical family based in Síol Anmchadha, in what is now south-east County Galway. Later members of the family were bishops of Clonfert and Archbishop of Tuam, as well as Abbots of the abbey of Abbeygormican in that county.
See also
Uilliam Ó Cormacáin Henry Ó Cormacáin
References http://www.ucc.ie/celt/published/T100005C/ https://archive.org/stream/fastiecclesiaehi04cottuoft#page/n17/mode/2up http://www.irishtimes.com/ancestor/surname/index.cfm?fuseaction=Go.&UserID= The Surnames of Ireland, Edward MacLysaght, 1978.