Anglo-Siamese Treaty of 1909
The Anglo-Siamese Treaty of 1909, also known as the Bangkok Treaty of 1909, was an agreement between the United Kingdom and the Kingdom of Siam (now Thailand). It was signed on 10 March 1909 in Bangkok, with ratifications exchanged in London on 9 July 1909.
Source: Wikipedia — Anglo-Siamese Treaty of 1909 (CC BY-SA 4.0)