In 1301, Philip had the bishop of Pamier arrested for treason. Boniface called French bishops to Rome to discuss Philip's actions. In response, Philip convoked an assembly of bishops, nobles and grand bourgeois of Paris in order to condemn the Pope. This precursor to the Estates General appeared for the first time during his reign, a measure of the professionalism and order that his ministers were introducing into government. This assembly, which was composed of clergy, nobles, and burghers, gave support to Philip. Boniface retaliated with the celebrated bull "Unam Sanctam" (1302), a declaration of papal supremacy. Philip gained a victory, after having sent his agent Guillaume de Nogaret to arrest Boniface at Anagni. The pope escaped but died soon afterward. The French archbishop Bertrand de Goth was elected pope as Clement V and thus began the so-called Babylonian Captivity of the papacy (1309–76), during which the official seat of the papacy moved to Avignon, an enclave surrounded by French territories, and was subjected to French control.