the Shan state of Thibaw (Hsipaw), which too was fighting Mohnyin's raids on its territory. Mohnyin was attacking other Shan states when it was not raiding Ava. It seized Bhamo from Thibaw in 1512 in the east, and raiding Kale in the west. The Ava-Thibaw alliance was able to retake Shwebo for a time but Mohnyin proved too strong. By the early 1520s, Chief Sawlon of Mohnyin had assembled a confederation of Shan states (Mogaung, Bhamo, Momeik, and Kale) under his leadership. Prome had also joined the confederation. The confederation wiped out Ava's defences in Shwebo in 1524. Finally on 25 March 1527, the forces of the confederation and Prome took Ava. The Confederation later sacked Prome in 1532/33 because Sawlon felt that Prome had not given sufficient help. Toungoo period Toungoo Empire Beginnings 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. Lower Burma and Central Burma (1534–1545) When Tabinshwehti came to power in 1530, Toungoo was now the only ethnic Burman-led kingdom, and one surrounded by much larger kingdoms. Fortunately for Toungoo, the Confederation was distracted by internal leadership disputes, and Hanthawaddy, then the most powerful kingdom of all post-Pagan kingdoms, was weakly led. Tabinshwehti decided not to wait until the larger kingdoms' attention turned to him. Tabinshwehti and his deputy Bayinnaung selected a weakly led Hanthawaddy as their first target. Their initial dry-season raids in 1534–1535, 1535–1536, and 1536–1537 all failed against Pegu's fortified defences aided by foreign mercenaries and Portuguese firearms. Toungoo armies had only 6,000 to 7,000 men, and did not yet have access to firearms. Finally, Toungoo used a stratagem to create a split in the Hanthawaddy camp, and took Pegu