Sikkim emerged as a polity in its own right, distinct from the hill kingdoms of Nepal and Bhutan. The kings of Sikkim saw themselves as protectors of their people who were obliged to maintain their independence.
Its original name was "Drenjong" (meaning "The Land of Thunder"), but as time passed, its pronunciation contracted and Sikkim became the official name. The Lepchas, who are at the base of Sikkim's ethnic origin, called it "Nye-mae-el", meaning "paradise". In history, Sikkim is known to Tibetans and Bhutanese as "Sikkim" or Deshin."
The dynasty ruled for 192 years from AD 1705 until 1975, during which period the kingdom witnessed a flourishing trade between India and Tibet along with many cultural changes such as the introduction of Sikkimese thangka painting and monastic Buddhism. As Sikkim was never colonised by the British it has retained much more traditional character than either West Bengal or Assam.
It became an Indian protectorate in 1950 and merged itself with India in 1975 following a referendum, since when it has remained a state in the Indian Union.
In 1991, Sikkim became the first state in India to achieve a 100% literacy rate. In 2009 it was ranked third among Indian states according to the Human Development Index.