Thailand, officially the Kingdom of Thailand and historically known as Siam (the official name until 1939), is a country in Southeast Asia on the Indochinese Peninsula. With a population of almost 66 million, it spans 513,115 square kilometres (198,115 sq mi). Thailand is bordered to the northwest by Myanmar, to the northeast and east by Laos, to the southeast by Cambodia, to the south by the Gulf of Thailand and Malaysia, and to the southwest by the Andaman Sea; it also shares maritime borders with Vietnam to the southeast and Indonesia and India to the southwest. Bangkok is the state capital and largest city. Thai peoples migrated from southwestern China to mainland Southeast Asia from the 6th to 11th centuries. Indianised kingdoms such as the Mon, Khmer Empire, and Malay states ruled the region, competing with Thai states such as the Kingdoms of Ngoenyang, Sukhothai, Lan Na, and Ayutthaya, which also rivalled each other. European contact began in 1511 with a Portuguese diplomatic mission to Ayutthaya, which became a regional power by the end of the 15th century. Ayutthaya reached its peak during the 18th century, until it was destroyed in the Burmese–Siamese War. King Taksin the Great quickly reunified the fragmented territory and established the short-lived Thonburi Kingdom (1767–1782), of which he was the only king. He was succeeded in 1782 by Phutthayotfa Chulalok (Rama I), the first monarch of the current Chakri dynasty.