 was born in the spring of 704, just a few months before his father died.Beckwith states that in the winter of 704-705, Lha ("Balpho" or Lha Balpo), one of the sons of Tridu Songtsen, took the throne, but Thrimalö (), the empress dowager, wife of the second emperor, Mangsong Mangtsen, and mother of Tridu Songtsen, "dethroned Lha in favor of the infant Rgyal Gtsug ru, the future Khri gtsug brtsan, popularly known as Mes ag tshoms.Revolts and executions accompanied the virtual coup, but the "Annals" and Chinese sources have little to report on them.