BARCLAY, WILLIAM. — Scottish jurist and theologian, b. at Aberdeen around 1543 and d. at Angers on 3 July 1608. After having spent his youth at the Scottish court, when already advanced in age he devoted himself to study, first at Aberdeen, then at Bourges, where he was a pupil of Cuiacius and Donellus. In 1578 he obtained the chair of law at Pont-à-Mousson and was appointed by the Duke of Lorraine as State Councillor. In 1603, when James I ascended the throne, he returned to England; but, refusing to abjure, he was forced to return to France, where at Angers he was entrusted with the chair of law.
His learning and firmness of character secured for him in his time a deservedly wide reputation. A Catholic, but strongly Gallican in outlook, he became the champion and defender of royal power against the encroaching democratic theories and against papal supreme authority, concerning whose power he held certain views and against which he levelled accusations that were entirely unjust, while still considering himself a faithful Catholic. St. Roberto Bellarmino and Lessius ably refuted him, respectively in the Tractatus de potestatis Summi Pontificis in rebus temporalibus adversus Guil. Barclaum (Rome 1610), and in the Defensio potestatis Summi Pontificis adversus librum regis Magnae Britanniae, Guil. Barclay Scoti et M. Georgii Blacuelli (Saragossa 1611). His works: De regno et regali potestate adversus Buchananum, Brutum et Boucherium et reliquus monarchomachos II. 6 (Paris 1600, 1612); In titulos pandectarum de rebus creditis et de jurejurando commentarii (there 1605); De potestate papae, an et quatenus in principes saeculares jus et imperium habeat (London 1609; Pont-à-Mousson 1609; placed on the Index on 26 April 1613).