Whithorn Priory is located in Wigtownshire, Galloway. It was founded about the middle of the twelfth century, in the reign of David I, by Fergus, Lord of Galloway, with Gille Aldan, Bishop of Galloway, for Premonstratensian Canons, referred colloquially in Britain as the White Canons. The canons of Whithorn formed the chapter of the Diocese of Galloway, which was re-established about the same time, also by Fergus, the old succession of bishops having died out in the 8th or 9th centuries.
The prior stood next in rank to the bishop, as we see from the order of signatories to an espiscopal charter early in the thirteenth century; and he and his community enjoyed the right of electing the bishop, although this right was occasionally overruled in favour of the secular clergy by the Archbishop of York, of which see Galloway was a suffragan for several centuries. It continued to belong to the bishopric until the revolution of 1688, at which date that see was the richest in the kingdom next to St. Andrews and Glasgow.
The priory church, which served also as the cathedral of the diocese, had a long nave without aisles, a choir of about the same length, and a lady chapel beyond. In 1684 the nave and western tower were still intact; but the existing remains consist only of the roofless nave and the extensive vaulted crypts constructed under the eastern end of the church. Such restoration as was possible has been carefully carried out by the third Marquis of Bute.