Passage: Following the beginning of British rule in neighbouring India, Sikkim allied with Britain against their common adversary, Nepal. The Nepalese attacked Sikkim, overrunning most of the region including the Terai. This prompted the British East India Company to attack Nepal, resulting in the Gurkha War of 1814. Treaties signed between Sikkim and Nepal resulted in the return of the territory annexed by the Nepalese in 1817. However, ties between Sikkim and the British weakened when the latter began taxation of the Morang region. In 1849, two British physicians, Sir Joseph Dalton Hooker and Dr. Archibald Campbell, the latter being in charge of relations between the British and Sikkimese governments, ventured into the mountains of Sikkim unannounced and unauthorised. The doctors were detained by the Sikkimese government, leading to a punitive British expedition against the kingdom, after which the Darjeeling district and Morang were annexed to British India in 1853. The invasion led to the Chogyal of Sikkim becoming a titular ruler under the directive of the British governor.Sikkim became a British protectorate in the later decades of the 19th century, formalised by a convention signed with China in 1890. Sikkim was gradually granted more sovereignty over the next three decades, and became a member of the Chamber of Princes, the assembly representing the rulers of the Indian princely states, in 1922.

Question: Who was Sikkim's enemy?
Nepal