15th-century carving of a warrior displaying the arms of Butler
Jerpoint Abbey, County Kilkenny

Picture Source

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Referenced on p22, WAR - 143 Galloglass 1250-1600, Gaelic Mercenary Warrior by Fergus Cannan

See also:
Drawings on the wall of Abbey Knockmoy, Co. Galway, Ireland, 15th Century
Other Irish Illustrations of Costume & Soldiers