During the thesaphiban reforms at the end of the 19th century, both Nakhon Si Thammarat and Pattani were incorporated into the central state. The area was subdivided into 5 monthon, which were installed to control the city states (mueang). Minor mueang were merged into larger ones, thus forming the present 14 provinces. With the Anglo-Siamese Treaty of 1909 the boundary to Malaysia was fixed. Kedah came under British control, while Pattani stayed with Siam.