Burma ceded the region south of Salween river to the British after the First Anglo-Burmese War (1824–1826) per the Treaty of Yandabo. The British and the Siamese signed a boundary demarcation treaty on 20 June 1826, and another one in 1868. Mawlamyine (Moulmein) became the first capital of British Burma. The British seized all of Lower Burma after the Second Anglo-Burmese War of 1852, and moved the capital to Yangon (Rangoon). After 1852, Tanintharyi Region consisted the entire southeastern Myanmar, including today's Mon State, Kayin State, and Taungoo District, in Bago Region. Mawlamyine was the capital of Tanintharyi.