On 25 July 1414, with a fleet consisting of four galleys and two other vessels carrying contingents of infantry and cavalry, departed Constantinople for Thessalonica. The purpose of this force soon became clear when he made an unannounced stop at Thasos, a normally unimportant island which was then under threat from a son of the lord of Lesbos, Francesco Gattilusio. It took Manuel three months to reassert imperial authority on the island. Only then did he continue on to Thessalonica, where he was warmly met by his son Andronicus, who then governed the city.