The Byzantine Emperor, John V Palaiologos visited Louis in Buda in early 1366, seeking his assistance against the Ottoman Turks, who had set foot in Europe. This was the first occasion that a Byzantine Emperor left his empire to plead for a foreign monarch's assistance. According to Louis's physician, Giovanni di Conversino, at his first meeting with Louis, the emperor refused to dismount and to take off his hat, which offended Louis. John V pledged that he would promote the union of the Byzantine Church with the Papacy, and Louis promised to send him help, but neither the emperor nor Louis fulfilled their promises. Pope Urban encouraged Louis not to send help to Constantinople before the emperor guaranteed the Church union.