 Since the idea was put forward by the German art historian, Friedrich Rintelen in 1912, many scholars have expressed doubt that Giotto was the author of the Upper Church frescoes.According to some late sources, the Sultan gave Francis permission to visit the sacred places in the Holy Land and even to preach there.All that can safely be asserted is that Francis and his companion left the Crusader camp for Acre, from where they embarked for Italy in the latter half of 1220.