One of the earliest treaties regarding the boundaries in the western sector was issued in 1842 following the Dogra–Tibetan War. The Sikh Empire of the Punjab region had annexed Ladakh into the state of Jammu in 1834. In 1841, they invaded Tibet with an army. Chinese forces defeated the Sikh army and in turn entered Ladakh and besieged Leh. After being checked by the Sikh forces, the Chinese and the Sikhs signed a treaty in September 1842, which stipulated no transgressions or interference in the other country's frontiers. The British defeat of the Sikhs in 1846 resulted in transfer of sovereignty over Ladakh to the British, and British commissioners attempted to meet with Chinese officials to discuss the border they now shared. However, both sides were sufficiently satisfied that a traditional border was recognised and defined by natural elements, and the border was not demarcated. The boundaries at the two extremities, Pangong Lake and Karakoram Pass, were reasonably well-defined, but the Aksai Chin area in between lay largely undefined.