"Of interest to the discussion of the legend of Prester John is a passage in which Benjamin described a powerful king in the East. According to the narrative, the king’s name was Kofar-al-Turak, and this Asian king successfully destroyed the king of Persia. Benjamin claimed that Kofar-al-Turak’s forces 'slew many of the Persian army, and the king of Persia fled with only a few followers to his own country.'
The account seems contemporaneous with the 1141 defeat by the Kara-Khitai of the Kara-Khanids, who were nominally vassals of the Seljuks. The idea that the forces of Islam could be defeated by conquerors from the East – especially if they were fellow Christians – no doubt was welcome news in Europe. The series of twelfth and thirteenth century papal and royal embassies to the Turkic nomads known collectively as the Mongols was in part due to the credence placed in the account of
Benjamin of Tudela."