Portuguese and Dutch traders made the first western contact with East Timor in the early 16th century. Sandalwood and spice traders, as well as missionaries, maintained sporadic contact with the island until 1642, when the Portuguese moved into Timor in strength. The Portuguese and the Dutch, based at the western end of the island in Kupang, battled for influence until the present-day borders were agreed to by the colonial powers in 1915. Imperial Japan occupied East Timor from 1942-45. The territory of the Dutch East Indies, including West Timor, gained independence as the Republic of Indonesia in 1949.
Following a military coup in Lisbon in April 1974, Portugal began a rapid and disorganized decolonization process in most of its overseas territories, including East Timor. Political tensions--exacerbated by Indonesian involvement--heated up, and on August 11, 1975, the Timorese Democratic Union Party (UDT) launched a coup d'état in Dili. The putsch was followed by a brief but bloody civil war in which the Revolutionary Front for an Independent East Timor (FRETILIN) pushed UDT forces into Indonesian West Timor. Shortly after the FRETILIN victory in late September, Indonesian forces began incursions into East Timor. On October 16, five journalists from Australia, Britain, and New Zealand were murdered in the East Timorese town of Balibo shortly after they had filmed regular Indonesian army troops invading East Timorese territory. On November 28, FRETILIN declared East Timor an independent state, and Indonesia responded by launching a fullscale military invasion on December 7. On December 22, 1975 the UN Security Council called on Indonesia to withdraw its troops from East Timor.