archbishop of York from 1070, who opposed the primacy of the archbishopric of Canterbury (Canterbury, archbishop of) over that of York. Consecrated by Archbishop Lanfranc of Canterbury, Thomas professed obedience to Lanfranc personally rather than to the see of Canterbury. He attempted to administer the church in the English Midlands as if his office were independent of Lanfranc's, but church councils at Winchester and Windsor in 1072, acting on questionable documentary evidence, decreed in favour of Canterbury's precedence.

Thomas owed his advancement to Odo, bishop of Bayeux and half brother of William I the Conqueror. As archbishop, he reorganized religious activity in the north of England following William's devastation of the area. He began the development of St. Peter's Cathedral, York (known as York Minster), one of England's great medieval church buildings.