After he was finally driven out of Ava (Inwa) in October 1551, he fled south to Pegu (Bago) where he was given protection by King Bayinnaung of Toungoo Dynasty.
[2] Three tumultuous years later, after his father's death c. September 1545, the 29-year-old chief of Mobye succeeded the Ava throne with the royal style of Narapati III.
[3] Narapati III inherited not only an ongoing war with Toungoo but also an active Mohnyin-backed rebellion in Sagaing by Sithu Kyawhtin.
The Ava "Kingdom" had already lost all of Central Burma from Pagan (Bagan) southward since 1544, and further split into two halves: the Mohnyin-controlled west of the Irrawaddy (present-day Sagaing Region and southern Kachin State), and Hsipaw/Onbaung-controlled eastern half (approximately, northern Mandalay Region and western Shan State).
Unable to fight two wars, Narapati III sued for peace with Toungoo, agreeing to cede all of Central Burma.
[1] He was one of four former kings (along with Sithu Kyawhtin of Ava, Mekuti of Lan Na and Maha Chakkraphat of Siam) honored by Bayinnaung at the opening ceremony of the newly rebuilt Kanbawzathadi Palace on 16 March 1568.