Like every emperor from the recapture of Constantinople down to 1453, Andronicus turned his attention to the West and sought to obtain aid against the Turks, even at the price of coercing his people into a Union with Rome. The Turks had invaded Macedonia and attacked Euboea and Athens. As the southern portion of the Balkan peninsula was still ruled in part by the descendants of the crusading barons and by the remnant of the Catalans, there was reason to believe that the pope would be ready to arouse the West against the common enemy of Christendom. Accordingly the emperor took advantage of the passage of Dominican missionaries through Constantinople from Tartary to convey to Pope John the Twenty-second his desire for Union and his request for aid. The pope replied by sending preachers and by urging the emperor to do all he could to accomplish his part. His successor in 1335 grew alarmed at the attacks made by the Turks by sea on various places in the Mediterranean, and finding that the Catalans had seized Athens from Gautier de Brienne, who held it as his duchy, he excommunicated them. He invited Andronicus to join the king of France and Naples in a Crusade against the Turks which the Venetians and the Genoese had promised also to aid. The emperor gladly gave his consent and sent a number of ships, but the needs of Cyprus, which was being attacked by the Saracens, were decided to be more pressing than those of the empire, and the Crusade was not proceeded with. Andronicus in 1339 sent Barlaam, the author of many controversial works, to the pope, at that time in Avignon. On his arrival he pointed out that the Turks had seized the seats of four metropolitan sees, and he suggested that as a condition of the Union of the Churches the Turks should be expelled from Asia Minor. The pope recognised the desirability of such an attempt as keenly as many of his successors, but saw that the condition was impossible. [Sidenote: Death of Andronicus the Third. Reign of John (1341 to 1391), Cantacuzenus (1342 to 1355.)]