 In Donald Nicol's opinion, had Kantakouzenos remained at Constantinople, his authority might have remained secure. As the megas domestikos and regent however, he had the duty of dealing with the Empire's various enemies, who sought to take advantage of Andronikos'death. Dušan had invaded Macedonia, the Emir of Saruhan raided the coasts of Thrace, and Tsar Ivan Alexander of Bulgaria threatened war. In July Kantakouzenos left the capital at the head of the army, leaving control of the government to Apokaukos, whom he still believed loyal to him. Kantakouzenos' campaign proved successful. He persuaded Dušan to withdraw and repulsed the Turkish raiders, while Ivan Alexander, threatened by a fleet from the Emirate of Aydin, renewed his peace treaty with Byzantium. To crown this success, Kantakouzenos received an embassy of the Latin barons of the Principality of Achaea in the Morea. They expressed readiness to surrender the country in exchange for a guarantee of their property and rights. It was a unique opportunity, as Kantakouzenos himself recognized in his memoirs, since if successful, the Catalan-controlled Duchy of Athens was bound to follow, consolidating Byzantine control over Greece.
