[1] Unlike his two elder brothers, however, David X and George IX, Bagrat never came to the throne of Kartli.
Bagrat received in appanage the princedom of Mukhrani and the title of High Constable of Upper Kartli in reward for his vital assistance to his brother David X against the aggression from George II, a neighboring Georgian Bagratid ruler of Kakheti, in 1512.
Bagrat withheld a Kakhetian siege of his fortress on the river Ksani and forced George II to withdraw.
In 1513, he captured George in an ambush and put in prison where the king died, leaving Kakheti vulnerable to Bagrat's raids.
He authored a polemical work A Story of Religion of Ismaelite Infidels (მოთხრობაჲ სჯულთა უღმერთოთა ისმაილიტთაჲ), a Christian apology critical of Islam.