Chagatai Khan was a son of Genghis Khan, a prominent figure in the early Mongol Empire, and the first khan of the Chagatai Khanate. The second son of Genghis's wife Börte, Chagatai was renowned for his masterful knowledge of Mongol custom and law, which he scrupulously obeyed, as well as his harsh temperament. Because Genghis felt that he was too inflexible in character, most notably never accepting the legitimacy of his elder brother Jochi, he excluded Chagatai from succession to the Mongol throne. He was nevertheless a key figure in ensuring the stability of the empire after Genghis's death and during the reign of his younger brother Ögedei Khan.