May 1306. He made his only personal visit to Achaea shortly thereafter, accepting the homage of his vassals at Glarentza, and carrying out an unsuccessful campaign against the Despotate of Epirus. He left Guy II, Duke of Athens, as his bailli in Achaea. Meanwhile, Philip and Isabella relinquished their claims on Achaea on 11 May 1307 in exchange for the County of Alba. Second marriage In 1309, he accused Thamar of adultery, probably on a falsified charge. This freed him to take part in a complex marital pact. Catherine of Valois, the titular Latin Empress, had been betrothed to Hugh V, Duke of Burgundy, titular King of Thessalonica. This engagement was broken, and she married Philip on 29 July 1313, at Fontainebleau. In exchange, her maternal lands of Courtenay and other estates on the Continent were ceded to Hugh's sister Joan, who married Catherine's half-brother, Philip of Valois. Hugh V was betrothed to Joan, later Countess of Burgundy and Artois. (Hugh died before the marriage could be solemnized; Joan married Hugh's brother and successor Odo IV, Duke of Burgundy instead.) Philip ceded the Principality of Achaea (over which he retained suzerainty) to Matilda of Hainaut, who married Hugh's brother Louis of Burgundy on 29 July 1313. This donation was rather restricted: should the couple die without heirs, the Principality was to revert to the house of Burgundy, while Matilda enjoyed the usufruct for life. Nor could Matilda marry again without her suzerain's permission. To complete the separation of Eastern and Western claims, Hugh ceded his rights to Thessalonica to Louis, while Louis renounced his claims on his parents' inheritance in favor of Hugh. The engagement of Philip's eldest son Charles of Taranto to Matilda of Hainault was broken off, and he was engaged to Jeanne de Valois, younger sister of Catherine of Valois; his father also ceded to him the title of Despot of Romania and the claims thereto appertaining. Guelph-Ghibelline War In 1315, Philip was sent by his brother Robert of Naples to lead an army relieving the Florentines, who were threatened by the Pisans under Uguccione della Faggiuola. The Florentine-Neapolitan army was badly beaten at the Battle of Montecatini on 29 August 1315; Philip's younger brother Peter, Count of Gravina and his son Charles of Taranto were both killed. Frankish Greece The death of Louis of Burgundy without heirs in 1316 upset the Angevin plans for Achaea. Matilda