to the east as well as the Darjeeling and Kalimpong areas to the southwest. During the 18th century, Sikkim faced repeated raids from Bhutan and these areas often changed hands. After a Bhutanese attack in 1780, a settlement was reached, which resulted in the transfer of the Haa valley and the Kalimpong area to Bhutan. The Doklam plateau sandwiched between these regions is likely to have been part of these territories. The Chumbi Valley was still said to have been under the control of Sikkim at this point. Historians qualify this narrative, Saul Mullard states that the early kingdom of Sikkim was very much limited to the western part of modern Sikkim. The eastern part was under the control of independent chiefs, who did face border conflicts with the Bhutanese, losing the Kalimpong area. The possession of the Chumbi Valley by the Sikkimese is uncertain, but the Tibetans are known to have fended off Bhutanese incursions there. After the unification of Nepal under the Gorkhas in 1756, Nepal and Bhutan had coordinated their attacks on Sikkim. Bhutan was eliminated from the contest by an Anglo-Bhutanese treaty in 1774. Tibet enforced a settlement between Sikkim and Nepal, which is said to have irked Nepal. Following this, by 1788, Nepal occupied all of the Sikkim areas to the west of the Teesta river as well as four provinces of Tibet. Tibet eventually sought the help of China, resulting in the Sino-Nepalese War of 1792. This proved to be a decisive entry of China into the Himalayan politics. The victorious Chinese General ordered a land survey, in the process of which the Chumbi valley was declared as part of Tibet. The Sikkimese resented the losses forced on them in the aftermath of the war. British Raj period In the following decades, Sikkim established relations with the British East India Company and regained its lost territory with their help after an Anglo-Nepalese War. The British made Sikkim a de facto protectorate through the Treaty of Titalia (1817). However, the relations between Sikkim and the British remained rocky, and the Sikkimese retained loyalties to Tibet. Another treaty, Treaty of Tumlong in 1861, "confirmed" the protectorate status, and also excluded Tibetan influence from Sikkim. The Tibetan effort to retain their own suzerainty resulted in a clash at the Lingtu mountain in 1888. China, which exercised nominal suzerainty over Tibet, stepped in and signed a treaty on