Until 1975, Sikkim was an independent kingdom ruled by the Chogyals (Kings). The history of Sikkim's Chogyals dates back to the 16th century, when three holy men at Yoksom (also spelt as Yuksum or Yoksum), in West Sikkim, consecrated the first Chogyal. In 1975, following a popular movement to abolish the monarchy, Sikkim became the 22nd state of the Indian Union.
| 1642 AD | Chogyal Phunstok Namgyal Ascended the throne and consecrated first Chogyal of Sikkim, the capital was Yoksum. |
| 1670 AD | Tensung Namgyal Shifted capital to Rabdanste from Yoksum. |
| 1700 AD | Chakdor Namgyal Pendiongmu (Half sister) tried to dethrone Chakdor, who had to flee to Lhasa, but was reinstated as king with the help of Tibetans. |
| 1717 AD | Gurmed Namgyal Sikkim was attacked by Nepalese. |
| 1733 AD | Phunstok Namgyal Nepalese attacked Rabdanste - the capital of Sikkim. |
| 1780 AD | Tenzing Namgyal Chogyal flees to Tibet and died there. |
| 1793 AD | Tsudphud Namgyal Capital shifted from Rabanste to Tumlong. Treaty of Titalia in 1817 between Sikkim and British India was signed in which territories lost to Nepal were restored to Sikkim. Darjeeling was gifted to British India in 1835. Two Britishers Dr. Campbell and Dr. Hooker captured by the Sikkimese in 1849. Hostilities between British India and Sikkim and a treaty was signed in which Darjeeling was annexed to British India. |
| 1863 AD | Sidekong Namgyal |
| 1874 AD | Thutoh Namgyal Claude white appointed, as the first political of Sikkim in 1889. Capital shifted from Tumlong to Gangtok in 1894. |
| 1914 AD | Sidekong Namgyal |
| 1914 AD | Tashi Namgyal Treaty between India and Sikkim was signed in 1950. |
| 1963 AD | Palden Thondup Namgyal Sikkim became 2nd state of India on 16th May, 1975. Institution of the Chogyals came to an end. |
