Sivasagar, previously spelled Sibsagar ("the ocean of Lord Shiva"), is a town in Upper Assam, about 360 kilometers (224 mi) north east of Guwahati. It is the district headquarters of the Sivasagar district. It is well known for its Ahom palaces and monuments. Sivasagar today is also an important centre for the tea and oil industries. >Sivasagar, formerly known as Rangpur, was the capital of the Ahom Kingdom from 1699 to 1788. The Ahoms ruled Assam for six centuries, until their kingdom fell to the Burmese in 1819 and their ruling class was all but wiped out. The province was liberated by the British in 1825 but, owing to the state of anarchy which prevailed, it was completely annexed in 1826. For administrative purposes it was divided into three sub-divisions. It is said that the original name of Sivasagar was - 'Kalansupar' after the name of 'Kalansu Gohain' who resided in a village originally existed in the place where currently the Sivasagar tank is located. This town's main feature is the water body from which it takes its name. This is a 257-acre (1.04 km2) tank, also known as the Borpukhuri, which is at a higher elevation than the rest of the town, with three temples on its banks. Of these temples, the most prominent is the Sivadol, standing tall at 104 feet (32 m), drawing large crowds on Shiv Ratri. The other temples are the Vishnudol and Devidol. The Raj Kareng or royal palace and Talatal Ghar in Sivasagar complex standing magnificently near Joysagar tank bears the unfurled historical extravaganza unanimously. To its south stands the Fakua-Doul with eight symbols or octagonal in shape according to Taoist cosmology built by king Rudra Singha in 1703-04 A.D. for religious purpose, while the Ranghar known to be the first sports pavilion in Asia and built in its present shape by king Pramatta Singha in 1746 A.D., still proudly stands on the west. Out of the five capital towns of the Ahom rule, as many as four, Charaideo, Saragua, Gargaon and Rangpur, were within Sivasagar district leaving only Jorhat the last one in the adjacent district by the same name. >Earlier the Sivasagar town was bounded by Cherekapar on the east, Kathpar on the west, Joyrapar in the north and Dhuliapar on the south. Till the fag end of the Ahom rule the name Shivpur persisted. Only after the treaty of Yandaboo in 1826 A.D. when the East India Company and for that matter, the British government came to hold power, Shivpur along with Rangpur came to be known as Sibsagar. During the British rule, the Sibsagar district comprised three sub-divisions: Sibsagar, Jorhat and Golaghat. In 1912 A.D. the district headquarter was again shifted to Jorhat leaving Sibsagar only as a sub-divisional headquarter. It remained so till 1983 when on 1 July that year the Sibsagar and Golaghat sub-division of undivided Sibsagar district were declared as new districts by the Government of Assam. The newly constituted Sibsagar district has three sub-divisions, viz. Sibsagar, Nazira and Charaideo.