Complex sentence: Temujin's father, Yesügei (leader of the Borjigin clan and nephew to Ambaghai and Hotula Khan), emerged as the head of the ruling clan of the Mongols, but this position was contested by the rival Tayichi’ud clan, who descended directly from Ambaghai.
Split into simpler sentences: Temujin's father, Yesügei (leader of the Borjigin clan and nephew to Ambaghai and Hotula Khan), emerged as the head of the ruling clan of the Mongols. This position was contested by the rival Tayichi’ud clan, who descended directly from Ambaghai.