On finishing a translation of Seneca's "De Beneficiis" in 1418, he initiated extensive travels throughout Europe, which would keep him away from Portugal for the next ten years. After meeting with John II of Castile in Valladolid, he continued to Hungary, where he met with the Holy Roman Emperor Sigismund, and entered his service. He fought with the Imperial armies against the Turks and in the Hussite Wars in Bohemia and was awarded the march of Treviso in Northern Italy in 1422. In 1424 he left the Holy Roman Empire, meeting first with Murad II, Sultan of the Ottoman Empire, on the island of Patmos, and then continuing to Constantinople, capital of the Byzantine Empire; the hopeless position of the city against the Ottoman onslaught did not fail to impress him. From Constantinople he travelled to the Holy Land via Alexandria and Cairo.