In 1774 the then Lanna King with assistance from Siam finally drove the Burmese out of the Lanna Kingdom. The Lanna Kingdom eventually became part of Siam in 1892. The Lanna Kingdom was gradually dissolved and condensed into a 20,000 km² area centered around Chiang Mai. 1932 the whole Chiang Mai area officially became a province of Siam. In 1949 Siam officially became known as Thailand.