His mother, the queen, is identified as Driza Tökarma ( "the Bri Wife White Skull Woman"). The date of his birth and of when he took the throne are not certain. In Tibetan accounts, it is generally accepted that he was born in an Ox year of the Tibetan calendar, which means one of the following dates: 557, 569, 581, 593, 605 or 617 CE. He is thought to have ascended the throne at age thirteen (twelve by Western reckoning), by this reckoning c. 629.