Philip V of France adjudicated between them and decided that Walter had to pay off the sum of 7,000 livres tournois and his mother the rest. The Briennist claims were upheld by Pope Clement V and Pope John XXII, who took a firm stance against the Catalan Company: the Catalans were excommunicated, their attacks on fellow Christians excoriated, and attacks on them by the other Latin powers of Greece encouraged. Clement sought the intercession of King James II of Aragon to get the Catalans to abandon Athens, but the King's appeal to that effect was ignored. Clement further ordered the Knights Hospitaller to provide three or four galleys and men to defend the Brienne lands, and in 1314 commanded all Templar properties in the Duchy of Athens to be placed under the control of Gaucher V de Châtillon and to be used against the Catalans. The Briennist cause was undermined, however, by the persistent refusal of the Republic of Venice to support anti-Catalan ventures. Although the Venetians were often at odds with the Catalans over their claims to various fiefs in Euboea, in 1319 an accord was reached that established generally peaceful relations between the two over the next few decades. After 1321, Walter II repeatedly announced his intention to campaign in Greece and recover the Duchy of Athens, but financial constraints and his obligations to the King of Naples kept him occupied in Italy. In 1328, he even briefly concluded a truce with the Catalans. Thus it was not until 1330 that a serious effort got under way. In June 1330, Pope John XXII issued a crusading bull for Walter, and ordered prelates in Italy and Greece to preach for a crusade against the Catalans; shortly after, King Robert of Naples also gave the crusade his support, and allowed his feudatories to join it. The Venetians, on the other hand, renewed their treaty with the Catalans in April 1331. Sailing from Brindisi in August, Walter attacked first the Latin County palatine of Cephalonia and Zakynthos, and the Greek Despotate of Epirus, forcing them to recognize the overlordship of King Robert. From there he proceeded to invade the Duchy of Athens through northern Boeotia, but his campaign was a failure as the Catalans avoided battle and withdrew behind the walls of Thebes and Athens. Walter had neither the troops to overwhelm the Catalans nor the money to sustain a prolonged