  While in the De regimine Giles carefully avoids any reference to the thorny problem of the relationship between secular and ecclesiastical power, his later writings which are relevant for political theory deal first and foremost with ecclesiological problems. This holds true for his treatise De renuntiatione papae (1297–1298) where Giles defends the lawfulness of Celestine’s abdication against the arguments put forward by the Colonna cardinals in their first appeal against Boniface VIII. From the point of view of the history of political thought it is relevant that Giles argues that papal power, although of divine origin, is conferred on a particular individual by a human act, namely, by the election of the cardinals. Here Giles is countering the Colonna arguments that papal dignity cannot cease to reside in a pope until he dies, because the pontificate depends on God’s will, and stresses the fact that divine intention in this case becomes effective through the mediation of human agents, that is, through the consent of the electors and of the elected. A jurisdiction which is given by the consent of men, however, can also be removed by their consent through a reverse procedure. This does not amount to saying that the pope can be deposed (except in case of heresy), because, according to Giles, the pope is above the law and has no earthly authority above him. He can however, depose himself, that is, abdicate. Just as for his election the consent of his electors and of the elected was necessary, so also for the removal of the pope from office his consent is decisive (Eastman 1989, 1990, 1992). In this way Giles could dismiss arguments against the validity of Celestine’s abdication without admitting the possibility that the pope can be deposed, e. g., by the Council, as Boniface’s adversaries maintained.