Following the
loss of Malacca to the Dutch in 1641, the Portuguese there moved to
Gowa-
Kingdom of Tallo before they were expelled from there as well, forcing the remnants to move to either Dutch
Batavia or Portuguese-controlled
Timor and the
Solor Archipelago. Portuguese presence in the region had started since 1520 when they established
Lifau, and was largely represented by the
Topasses – "black Portuguese" consisting of mixed European-Asian descendants, freed slaves known as
Mardijkers, and some local Christians. The Topasses held significant influence in the island's politics. Relations between the "black" and "white" Portuguese communities soured at times, with open conflicts in the early 18th century as the Portuguese attempted to introduce direct rule by installing a governor. They were all subsequently removed, and there was no direct governorship from Portugal until 1748. Portuguese forces had invaded the interior of Timor in 1642, establishing their rule over the inland polities. The
Dutch East India Company (VOC) captured the Portuguese fort at
Solor in 1613 and established themselves in what is today
Kupang on Timor after defeating the Portuguese there in 1653. They allied with the native polities such as
Sonbai and
Amabi in 1655, but were defeated in ensuing conflicts. Intermittent wars and fighting occurred throughout the seventeenth and eighteenth centuries, with the Dutch reconstructing their fort at Kupang in 1746. During this period, Dutch control of Timor and surrounding areas was largely limited to their Kupang fort and surroundings. In early 1749, the ruler of Sombai (which was returned to Portuguese influence prior) reallied themselves with the Dutch and settled with their followers near Kupang, causing
Gaspar da Costa, leader of the Topasses, to gather an army from both the Topass and the local polities aligned to Portugal. On 18 October 1749, the ruler of
Amabi informed the Dutch of a large army assembling. Da Costa wanted to force Sombai to swear fealty to him, with the aid of Portuguese-aligned rulers in the area in addition to men from
Larantuka. The Amarassi
raja, one of the rulers aligned with da Costa, sent an envoy to attempt to convince the Kupang
raja and the Dutch to remain neutral in the conflict. ==Forces==