The establishment of the Buddhist kingdom under the Chogyal in the 17th century was followed by British rule in Sikkim and thereafter inclusion in India as an official state of the nation post- independence.
Sikkim emerged as a polity in its own right against a backdrop of incursions from Tibet and Bhutan, during which the kingdom enjoyed varying degrees of independence.
[citation needed] In the 7th century, Thekung Adek consolidated the Lepcha tribes and declared himself a Panu, a Tribal Religious and Administrative chief or king.
[11] Sikkim also finds mention in many Hindu texts because the Buddhist saint Guru Rinpoche or Padmasambhava is said to have passed through the land in the 9th century.
[citation needed] According to legend, the Guru blessed the land, introduced Buddhism to Sikkim and also foretold the era of the monarchy in the state, which would arrive centuries later.
The most popular states that in the 13th century, Guru Tashi, a prince from the Minyak House in Kham in Eastern Tibet, had a divine revelation one night instructing him to travel south to seek his fortunes.
The Dalai Lama sent the new Chogyal a silk scarf, the mitre of Guru Rinpoche and a sand image of him as a coronation present.
The Chogyal, along with the three lamas proselytised the Lepcha tribes into Buddhism and annexed the Chumbi Valley, the present-day Darjeeling district and parts of today's eastern Nepal.
[citation needed] Shortly after his coronation the new Chogyal appointed 12 kalon or ministers from the Bhutia community and split his kingdom into 12 Dzongs or administrative units, which each contained a fort.
Out of Sikkim's 104 revenue estates, 61 were leased to Kazis and thikadars for fixed sums, five were given to monasteries and fifteen were retained by the Chogyal for his private use.
[14] Thus Phuntsog Namgyal became the first King of the Kingdom of Sikkim and all the Kirat chiefs agreed to regard him as the supreme ruler.
The Tibetan people subsequently expelled the Bhutanese army, and called Chakdor Namgyal back to Sikkim.
With the arrival of the British in neighbouring India, Sikkim allied itself with them as they had a common enemy – the Gorkha Kingdom of Nepal.
This prompted the British East India Company to attack Nepal resulting in the Anglo-Nepalese War, which began in 1814.
They were detained by the Sikkim government at the instigation of the pro-Tibetan "mad Dewan" T. Namguey, which led to a punitive British expedition against the Himalayan kingdom.
In the same year, the signature of the Treaty of Tumlong effectively made Sikkim a de facto protectorate of the British.
A state visit to Darjeeling by Sidekong's half-brother, Chogyal Thutob Namgyal in 1873 failed to yield such results, and he returned to Tumlong disappointed.
The Tibetans occupied several of Sikkim's northern border forts, and the Chogyal and his wife were held prisoner by the British when they came to negotiate at Calcutta.
The two made an excellent acquaintance and the Crown Prince of Sikkim, Sidkeong Tulku was sent to study at Oxford University.
When Sidkeong came to power, he arranged widened sovereignty for Sikkim from King George's government and endorsed sweeping reforms in his short rule as Chogyal, which ended in 1914.
In 1918, Sikkim's independence in all domestic affairs was restored, and in the next decade, the kingdom embarked on a policy to end social ills, outlawing gambling, child labour, and indentured service.
In the 1950s, Sikkim was used by the American CIA as a base for secret operations supporting Tibetan guerillas opposed to Chinese control of Tibet.
Trouble began to brew for the crown even before the Chogyal assumed the throne, as Nehru, who had carefully preserved Sikkim's status as an independent protectorate, died in 1964.
The Chogyal, who responded to the increased pressure by drinking, was viewed by India as politically dangerous, especially after his wife, the American socialite Hope Cooke, advocated a return of certain former Sikkimese properties.
The two claimants did battle in the Indian court system for control of the considerable funds collected by the 16th Karmapa for the restoration and maintenance of Rumtek Monastery, located in Gangtok, Sikkim.
The Chinese, who recognise Ogyen Trinley Dorje as the true Karmapa, were unhappy about the court outcome which awarded the monastery funds to the other rival.
On 18 September 2011, a magnitude 6.9Mw earthquake struck Sikkim, killing at least 116 people in the state and Nepal, Bhutan, Bangladesh and Tibet, China.