BERENGAR OF TOURS (c. 1000–1088), rector of the schools of Saint-Martin in Tours and sometime archdeacon of Angers. Berengar was at the center of a eucharistic controversy in his own day and subsequently lent his name to a cluster of positions that more or less closely resembled his. He stands at one pole of a tension that has recurrently characterized Western thinking on the sacrament.

In 1059, under duress, Berengar took an oath formulated by Humbert, cardinal bishop of Silva Candida, to the effect that "the bread and wine which are laid on the altar are after consecration not only a sign [sacramentum], but the true body and blood of our Lord Jesus Christ, and they are physically [sensualiter] touched and broken by the hands of the priests and crushed by the teeth of the faithful, not only in a sign [sacramento] but in truth." The...