Complex sentence: Kazakh identity is of medieval origin and was strongly shaped by foundation of the Kazakh Khanate between 1456 and 1465, when several tribes under the rule of the sultans Janybek and Kerey departed from the Khanate of Abu'l-Khayr Khan.
Split into simpler sentences: Kazakh identity is of medieval origin and was strongly shaped by foundation of the Kazakh Khanate in 1456--1465. The formation of Khanate began when several tribes under the rule of sultans Janybek and Kerey departed from the Khanate of Abu'l-Khayr Khan.