Toghrul ( Tooril han; ), also known as Wang Khan or Ong Khan ( Wan han; ; died 1203) was a khan of the Keraites. He was the blood brother (anda) of the Mongol chief Yesugei and served as an important early patron and ally to Yesugei's son Temüjin, later known as Genghis Khan. The main source on his life is The Secret History of Mongols. Name "Wang Khan" was the name given to Toghrul by the Jurchen-led Jin dynasty of China; Wang means king or prince. During the 13th century, Toghrul was one of several Asian leaders who was identified with the legend of Prester John, but also King David, a brother to John. There's no credible proof that he was Christian. Early life He was born around 1130, to Nestorian family of Keraites. His father was Cyriacus Buyruk Khan, the leader of Keraites. Toghrul had a very difficult youth. The Merkits captured him during his childhood and he was reduced to slavery. It is possible that he left the Merkit after being freed by a ransom or simply escaped. However, according to the Secret History, he was again abducted at the age of thirteen by the Tatars, who also took his own mother. When Toghrul returned to the Keraites later, his father was near death. Toghrul took his place and commanded the Keraites around 1165. Reign In order to eliminate potential rivals, he started by killing his brothers between 1165 and 1171. One of them, namely Erke Qara managed to escape and fled to the Naimans, who were a neighboring tribe to the west of the Keraites. The two other brothers, Buqa-Timur and Tai-Timur Taïshi were executed. However, Toghrul's success was brief because his uncle only known with the title Gurkhan overthrew him. Toghrul fled with his daughter and a handful of faithful. He tried to get the help of the Merkits to overthrow Gurkhan in turn, but their leader, Toqto'a Beki, refused despite the fact that Toghrul offered him his daughter because the Keraites were very numerous. Being unsuccessful, Toghrul went to see the father of Temujin, Yesugei. He chose to help Toghrul because he had previously fought a battle with the Keraites against the Tatars. The Keraites were surprised when Yesugei attacked without having time to prepare. Despite the fact that the Keraits were much more numerous, their forces were dispersed throughout Central Mongolia. Toghrul resumed