The Sinhalese arrived in Sri Lanka late in the 6th century B.C., probably from northern India. Buddhism was introduced beginning in about the mid-third century B.C., and a great civilization developed at the cities of Anuradhapura (kingdom from circa 200 B.C. to circa A.D. 1000) and Polonnaruwa (from about 1070 to 1200). In the 14th century, a south Indian dynasty seized power in the north and established a Tamil kingdom. Occupied by the Portuguese in the 16th century and by the Dutch in the 17th century, the island was ceded to the British in 1796, became a crown colony in 1802, and was united under British rule by 1815. As Ceylon, it became independent in 1948; its name was changed to Sri Lanka in 1972. Tensions between the Sinhalese majority and Tamil separatists erupted into war in 1983. Tens of thousands have died in an ethnic conflict that continues to fester. After two decades of fighting, the government and Liberation Tigers of Tamil Eelam formalized a cease-fire in February 2002, with Norway brokering peace negotiations.