Gille Ísa Ua Maílín (died 1184)"Medieval Ireland: An Encyclopedia" Seán Duffy,S/ MacShamhráin,A/ Moynes, J: Abingdon, Routledge, 2005 was an Irish bishop in the 12th century:“A New History of Ireland” T. W. Moody, F. X. Martin, F.J. Byrne and Cosgrove, A: Oxford, OUP, 1976 he took the oath of fealty to Henry II in 1172 as Bishop of Mayo.
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