He escorted the Emperor on his Italian journeys and, in 1239, Frederick invested him with Thessalonica, which had originally been conquered by his grandfather in the aftermath of the Fourth Crusade.
Dia mengawal Kaisar dalam perjalanannya di Italia dan, pada tahun 1239, Friedrich menempatkannya di Tesalonika, yang semula ditaklukkan oleh kakeknya setelah perang Salib Keempat.