Leblanc, Guillaume a French prelate, was bar at Alby in 1561. The position of his uncle, a distinguished theologian of the same name, aided his access to ecclesiastical honors. Having been chamberlain to pope Sixtus V, he was appointed, in 1588, to the bishopric of Vence, which a bull of Clement VIII reunited, in 1591, with the episcopal see of Grasse. This reunion, which the chapter of Vence vigorously repelled, became to Leblanc a great source of embarrassment and litigation. He was even the object of an attempted assassination, and sought to destroy the act of union by the parliament of Aix. He died at Aix, November 21, 1601. For mention of his works, see Hoefer, Nouv. Biog. Generale, s.v.