After her first army was defeated in 1345, the attackers moved next into the territory ruled by James. In 1347, James asked Amadeus for help, and Amadeus sent an army. That army swept the attackers back through July of that year, with Amadeus joining the fighting in the last few weeks. John then recruited the help of Humbert II, Dauphin of Viennois, an old enemy of the Savoyards, and Thomas II, Marquess of Saluzzo. Together, they conquered the Angevin lands. Pope Clement VI spent 1348 negotiating a truce to end the fighting, which none of the combatants were satisfied with. From 1348 through 1351, the Black Death ravaged the lands of Savoy, halving the population in some villages. In 1348, many of the peasants thought that it was caused by Jews poisoning wells and fountains. Though the castellans in some places tried to protect them, quite a few were killed. In Chambéry, the Jews were locked in the castle for their protection, but a mob broke in and killed several. Court officers were then pressured into finding the remainder guilty of poisoning, executing eleven and charging the remainder a fine of 160 florins per month for the next six years. In 1349, Amadeus agreed to a treaty between himself, Amadeus of Geneva, James of Piedmont, and the House of Visconti, rulers of Milan, for mutual defence and assistance. This treaty included provisions for Galeazzo II Visconti to marry Bianca of Savoy, sister of the count. To honor the marriage in 1350, Amadeus created the Order of the Black Swan. In 1349 Humbert II de La Tour du Pin, Dauphin de Viennois, the last Dauphin de Viennois, surrendered his title and principality to the future Charles V of France. At the time the new Dauphin was grandson of the current King Philip VI of France and son to his heir apparent, the later John II of France. Humbert II retired into a Dominican monastery. In 1350, Guichard Tavel, the bishop of Sion and an ally of Savoy attempted to take the rights of some nobles in Valais, a frontier of Savoy. He and his staff were attacked in August 1351. Pope Clement VI excommunicated the rebels, and Amadeus sent in thirty knights.