The day he was invested as Vicar-General, he married by proxy Thamar Angelina Komnene, daughter of Nikephoros I Komnenos Doukas, Despot of Epirus.

Upon their marriage, Charles ceded to Philip the suzerainty of Achaea and the Kingdom of Albania, and all his rights to the Latin Empire and the Lordship of Vlachia.

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.

[10] In exchange, her maternal lands of Courtenay and other estates on the Continent were ceded to Hugh's sister Joan the Lame, who married Catherine's half-brother, Philip of Valois.

[11]) 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.

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.

[11] In 1320, Eudes IV, Duke of Burgundy, after several protests, agreed to sell his rights to Achaea and Thessalonica to Louis, Count of Clermont for 40,000 livres.

In the meantime, the refractory Matilda of Hainaut was brought before the Papal court in Avignon, where she revealed that she had secretly married the Burgundian knight Hugh de La Palice.

[13] Philip continued to plot the recovery of the Latin Empire, making an alliance in 1318 with his nephew Charles I of Hungary for that purpose, but to no effect.