Located in a remote, hard-to-reach corner east of the Pegu Yoma range, Toungoo had always been a troublesome province. It raised repeated rebellions throughout the 14th and 15th centuries against its overlords at Pinya and Ava, usually with Hanthawaddy Pegu's help. In 1494, Toungoo raided Pegu's territory without its overlord Ava's permission, and barely survived a strong counterattack by Pegu in 1495-1496. Mingyi Nyo, viceroy of Toungoo, would not make war against the larger neighbour for the remainder of his life. Mingyi Nyo declared independence from Ava in 1510, and largely stayed out of the fighting raging between Ava and the Confederation of Shan States. When Ava fell to the combined forces of the Confederation and Prome in 1527, many people fled to Toungoo, the only region in Upper Burma at peace.. How many years long was Pegu's counterattack against Toungoo?