But Count Amadeus of Savoy not merely seized (1287) the castle built by the bishops (about 1219) on the Ile, but also (1288) the office of vicedominus [vidomne], the official through whom the bishop exercised his minor judicial rights.
In 1401 Amadeus VIII.
Amadeus did homage, in 1405, to the bishop for those of the newly acquired lands which he held from the bishop. But, after his power had been strengthened by his elevation (1417) by the emperor to the rank of a duke, and by his succession to the principality of Piedmont (1418, long held by a cadet branch of his house), Amadeus tried to purchase Geneva from its bishop, John of Pierre-Seise or Rochetaillee (1418-1422).
Oddly enough Amadeus did in the end get hold of the city, for, having been elected pope under the name of Felix V., he named himself to the vacant see of Geneva (1444), and kept it, after his resignation of the Papacy in 1449, till his death in 1451.
His first attempts against the French were successful; and the rupture between Victor Amadeus, duke of Savoy, and Louis XIV.