A German bishop, close to the German Emperor Barbarossa, who presented himself in the 12th century as the heir of the Magi, launched one of the greatest affabulations in history: a Christian kingdom led by the priest John, a descendant of the Magi, existed in the East and would be ready to take on the Muslim empire. An alleged letter sent to the Emperor of Byzantium by Priest John himself was enough for all the European monarchies and the Pope to send embassies around the world to be the one to obtain the favors of this descendant of the Magi. Artists have competed with each other in ingenuity to present fabulous portraits and maps of this mythical king, described in the Middle Ages as the most powerful man in the world! The French located him among the Mongols, the Italians in India, and the Portuguese in Ethiopia.