Pope Nicholas III on 25November. The Pope soon declared that no foreign prince could rule in Rome and reminded Charles that he had been elected senator for ten years. Charles swore fealty to the new pope on 24May 1278 after lengthy negotiations. He had to pledge that he would renounce both the senatorship of Rome and the vicariate of Tuscany in four months. On the other hand, Nicholas III confirmed the excommunication of Charles's enemies in Piedmont and started negotiations with Rudolf to prevent him from making an alliance against Charles with Margaret of Provence and her nephew, Edward I of England. The negotiations with Rudolf lay behind Nicholas' refusal to renew Charles's vicariate in Tuscany, to which Rudolf had appointed his own vicar. Charles announced his resignation from the senatorship and the vicariate on 30August 1278. He was succeeded by the Pope's brother, Matteo Orsini, in Rome, and by the Pope's nephew, Cardinal Latino Malabranca, in Tuscany. To ensure that Charles fully abandoned his ambitions in central Italy the Pope started negotiations with Rudolf about the restoration of the Kingdom of Arles for Charles's grandson, Charles Martel. Margaret of Provence sharply opposed the plan, but Philip III of France did not stand by his mother. After lengthy negotiations, in the summer of 1279 Rudolf recognised Charles as the lawful ruler of Provence without demanding his oath of fealty. An agreement about Charles Martel's rule in Arles and his marriage to Rudolf's daughter, Clemence, was signed in May 1280. The plan disturbed the rulers of the lands along the Upper Rhone, especially Duke Robert II and Count Otto IV of Burgundy. Charles had meanwhile inherited the Principality of Achaea from William II of Villehardouin, who had died on 1May 1278. He appointed the unpopular of Sicily, Galeran of Ivry, as his baillif in Achaea. Galeran could not pay his troops who started to pillage the peasants' homes. John I de la Roche, Duke of Athens, had to lend money to him to finance their salaries. Nicephoros I of Epirus acknowledged Charles's suzerainty on 14March 1279 to secure his assistance against the Byzantines. Nicephoros also ceded three townsButrinto, Sopotos and Panormosto Charles. Pope Nicholas died on 22August 1280. Charles sent agents to Viterbo to promote the election of one of his supporters, taking advantage of the rift between the late Pope's relatives and other Italian cardinals. When a riot broke out