INTRODUCTORY NOTICES. 181
brothers and several nephews. His father's brother, Gur-Khan by name (and here we have probably the origin of a part of the
confusions of Rubruquis), who had taken refuge with the Nai-
mans, got the chief of that tribe to take arms in his favour, and succeeded in displacing Tuli-Wang-Khan. The latter fled for
help to Yessugai, the father of Chinghiz, who gave it so effectually that Tuli was again restored to his dominions. After a reign of many years, however, he was again ejected, and reduced to a destitute condition. Hearing, by-and-by, of the rising influence of Temugin, afterwards called Chinghiz Khan, the son of his old friend, he visited him, was received in the most cordial manner, and was treated with the greatest consideration and liberality. This was in 1196. For some years the two chiefs conducted their raids in alliance, but differences sprang up between them ; the son of Wang-Khan entered into a plot to kill Temugin, and in 1202-3 they were in open war with one another. In the latter year, Temugin completely defeated the old Kerait in a battle fought between the Tuli and Kerulan rivers ; and the vanquished chief as he fled through the Naiman country, was slain by two of that tribe. This Potente, as Marco Polo calls him, it is whom that traveller identifies with Prester John, and in this Polo is followed by Montecorvino and Odoric. The idea must have been derived
from the oriental Christians ; for the title of Malik Yuhana
(King John) is applied expressly by Abulfaragius to the same
Tuli-Wang-Khan. But we have seen that the name reached
Europe more than a century before that chief's time.1
There seems to have been discovered no corroboration from oriental sources of the restoration of a measure of power and dignity to the descendants of the Kerait king who had wronged Chinghiz so grievously. But for this Marco's authority might well suffice, even were it not so fully confirmed by Montecorvino.
Much ingenuity has been expended by learned men to little purpose in devising an origin for the name of Prester John.
1 Pococke's Abulfaragius, p. 280 ; and for the preceding paragraphs see D'Ohsson, i, 48-83; Klaproth in Journ. Asiat., ser. i, tom. ix, 299-306, Pauthier, Le Pays de Tanduc et les Descendants du Prêtre Jean, Paris, 1862; Ritter, vol. ii, pp. 253-295; and especially D'Avezac in his introduction to Carpin.