During the thirteenth century it was the vain hope of the Popes and of the Christian kings of Europe to gain the alliance of some great power in the East—either the Mongols or Prester John—as an offset to Turkish encroachments on the Crusaders’ frontiers.[1334] Perhaps we may detect the beginnings of this policy in a letter of Pope Alexander III (1177) to John, “Magnificus rex Indorum sacerdotum sanctissimus.”[1335] The Pope informs the great king that he has heard of his piety through a certain Master Philip, papal physician, who had held conversation with distinguished and honorable persons of his realm. Consequently Alexander was sending this Philip to expound to him the tenets of Western Christianity and to convert him to the true Catholic faith. It seems probable that Alexander was acquainted with the supposed letter of Prester John to the Byzantine Emperor, though there is also strong probability that he had confused the stories of the Asiatic Prester John with reports regarding the Christian kingdom of Abyssinia—a source of much confusion at a later period than ours. GOG AND MAGOG The northern part of Asia was the reputed seat of the terrible tribes of Gog and Magog, whose eruption at the Last Day was destined to bring about the destruction of the human race. We have seen that Biblical prophecies were combined with the story of Alexander the Great’s enclosing of these tribes behind great walls. The legend appears in our period under various forms. Most of the maps show Gog and Magog, usually surrounded by a wall; some add disparaging epithets, such as “gens immunda.” Matthew Paris on his map of Palestine indicates in the north the walls whereby King Alexander the Great shut in Gog and Magog and states in the explanatory legend that from this same direction came the Tatars.[1336] In the _De imagine mundi_[1337] we find a simple statement that between the Caspian Mountains and the sea of that name dwelt those tribes who had been walled in by Alexander the Great, Gog and Magog, the fiercest of all peoples, eaters of the raw flesh of wild beasts and of human beings. The Moslems had placed Gog and Magog in the farthest corner of northeastern Asia: and in John of Seville’s translation of Al-Farghānī’s _Astronomy_ we find the land of Gog at the easternmost extremity of the sixth and seventh “climates” (those farthest north).[1338] Lambert li Tors speaks in the Romance of Alexander of “Gos et Magos” among the vassals of Porus: though they came forth with four hundred thousand men, Alexander, after he had defeated Porus, chased them back into the defiles of the mountains, where he shut them in with a great wall.[1339] In a later part of the Romance, the subdivision of Alexander’s kingdom at his death is explained: to Antigonus was given Syria and Persia as far as Mount Tus, together with the duty of standing guard over Gog and Magog.[1340] Otto of Freising also mentions these