A Very Short History of Sikkim
Nestled in the mountains between India and Tibet, Sikkim's culture has long been a mixture of traditional animist beliefs, Buddhism — which became the dominant religion in the eighth century — and Hindu influences from neighboring Bengal and Nepal.
Long an independent monarchy, in the 19th century Sikkim ceded present-day Darjeeling to the British. In exchange, the rest of the country was made a suzerain state of the empire, meaning it maintained internal autonomy but let Britain handle its external affairs. This agreement stuck after Indian independence in 1947, but things soon became complicated for the small country. Refugees poured into Sikkim after China's 1959 crackdown in Tibet, and India established an increased military presence along the border near Lhasa. Meanwhile, the ethnic makeup of Sikkim had been transformed by years of heavy immigration from Nepal; the country was now a Hindu majority controlled by a Buddhist monarchy and clergy.
Things came to a head in 1975, when Indian Prime Minister Indira Gandhi organized a referendum that abolished the monarchy and formally incorporated Sikkim into India. Whether these actions were an invasion, annexation, or national security necessity depends on whom you ask.
For more, read the feature story "East, West, and Ten-drel."