Cyriacus Buyruk Khan

Qurchaquz Buyruk Khan was a 12th-century Nestorian leader of Keraites. He was a son of Marqus Buyruk Khan.

Name
His name is written in The Secret History of the Mongols as Qurčaqus. According to Volker Rybatzki and Christoph Baumer its original form could be Cyriacus, a Syriac name. While per Lev Gumilev, original form may be Gregorius as well.

Reign
He succeeded Kerait ruler Sariq Khan (according to Timothy May, he was his father, while Isenbike Togan says Sariq was just pre-Christian name of Marcus Buyruk Khan ) in 1150. He soon emerged as one of the dominant powers in the steppe following destruction of Liao Dynasty by Jurchens. However, this situation soon challenged by Merkits and Tatars who kidnapped his son Toghrul in 1135. He soon reorganized the khanate between his sons. Center was Karabalgasun, while Toghrul ruled western part of the khanate as a subordinate to his uncle Gurkhan. His other sons Tai Temür Taishi and Yulamacus (as his subordinate) respectively granted Karaa and Boroo river banks, on the east. He soon died in 1165, his son not approving his division, claimed the throne for himself as his eldest son and sole ruler.

Family and descendants
He was married to a certain woman called Ilma who bore him Toghrul and Töre Qaimish, a daughter of Naiman ruler Betegin Oba Kötürchi Buyruq Khan. According to Jami at-Tawarikh, Töre Qaimish was engaged in witchcraft. Being worried about this Cyriacus ordered one of his concubines to kill her. Then, wishing to hide this fact, under a suitable pretext, he killed both of his concubines.

He had many sons including Toghrul, Erke Qara, Tai Temür Taishi, Yulamacus, Jakha Gambhu and Buqa Temür. Through his granddaughter Sorghaghtani Beki, he became ancestor of Toluids - rulers of Ilkhanate and Yuan dynasty.