Mahārāja Ambarīṣa had three sons, named Virūpa, Ketumān and Śambhu. The son of Virūpa was Pṛṣadaśva, and his son was Rathītara. Rathītara had no sons, but when he requested the favor of the great sage Aṅgirā, the sage begot several sons in the womb of Rathītara’s wife. When the sons were born, they became the dynasty of Aṅgirā Ṛṣi and of Rathītara.