January 1755, capturing the Irrawaddy delta and Dagon (Yangon) by May. The French defended Syriam and held out for another 14 months but eventually fell in July 1756, ending French involvement in the war. The fall of the 17-year-old southern kingdom fell soon after in May 1757 when Pegu was sacked. Lan Na, Martaban, Tavoy and Sandoway all submitted to Alaungpaya after Pegu's fall. Manipur (1756–1758) Alaungpaya, who grew up watching the Manipuri raids ransacking his home region year after year, was determined to return the favour as soon as he was able. In early 1756, he sent an expedition force to Manipur to "instill respect". The Burmese army defeated the Manipuri army, and ransacked the entire country, which the Manipuris call the First Devastation. After Lower Burma was conquered, Alaungpaya himself led another expedition in November 1758, this time to place the Burmese nominee to the Manipuri throne. His armies invaded by the Khumbat route in the Mainpur valley, and overcame fierce Manipuri resistance at Palel, on their march to Imphal, the Manipuri capital. After Palel, the Burmese entered Imphal without firing a shot. The Konbaung armies, according to the Manipuris, then inflicted "one of the worst disasters in its history". He brought back many Manipuri cavalry, who became an elite cavalry corps (the Cassay Horse) in the Burmese army. The Manipuri raja Ching-Thang Khomba (Jai Singh) fled into English Bengal, and would attempt to regain his kingdom for the next 24 years. With English East India Company's arms support, he invaded Manipur in 1763 but was driven back by Hsinbyushin in early 1764. Negrais (1759) The English East India Company had seized Negrais (Haigyi Island) at the southwestern tip of the Irrawaddy delta since April 1753 because they were concerned about the French influence over Pegu, and wanted their own foothold in Lower Burma. During the war with Hanthawaddy, Alaungpaya even offered to cede the island to England in return for military help. But no military help materialised. The English claimed they could not spare any arms because they too were engaged in their own bitter Seven Years' War against the French. Yet the company's agents sold ammunition and muskets to the Mon rebels in 1758. On 6 October 1759, a 2,000-strong Konbaung battalion overran the English fort, ending the first English colonial establishment in Burma for the time being. Siam (1759–1767) By 1759, Alaungpaya had reunified all