In a certain plain among these pasture lands [of the Carcathayans] was a Nestorian, a mighty shepherd and lord of all the people called Naimans, who were Nestorian Christians. On the death of Coir Chan, this Nestorian set himself as king and the Nestorians called him King John, and they used to tell of him ten times more than the truth. For the Nestorians coming from these parts do this kind of thing-- out of nothing they make a great rumour… I passed through his pasture lands and nobody knew anything about him with the exception of a few Nestorians.
[...]This John had a brother by the name of Unc, like him a mighty shepard, and he was beyond the pastures of these Carcathayans, separated from his brother by a distance of three weeks’ journey, and he was lord of a little town called Caracorum,... King John died without an heir and his brother Unc grew rich and had himself called Chan and used to send his herds and flocks as far as the Mongol boundaries… And the Tartars and Mongols made him their leader and captain.”
