What is "keraites"

The Keraites (also Kerait, Kereit, Khereid ; ) were one of the five dominant Turco-Mongol tribal confederations ( khanates) in the Altai-Sayan region during the 12th century. They had converted to the Church of the East ( Nestorianism) in the early 11th century and are one of the possible sources of the European Prester John legend.

Their original territory was expansive, corresponding to much of what is now Mongolia. Vasily Bartold (1913) located them along the upper Onon and Kherlen rivers and along the Tuul river. They were defeated by Genghis Khan in 1203 and became influential in the rise of the Mongol Empire, and were gradually absorbed into the succeeding Turco-Mongol khanates during the 13th century.