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.
[2] Dutch accounts estimated "tens of thousands" of enemy forces, ranging from 20,000 to 50,000, although this figure was likely an exaggeration as Timor's population then was far below half a million.
[1] Da Costa was not supported by the Portuguese authorities, and also did not hold full control over the Topass – with the competing de Hornay family not participating in the battle.
[12] Aside from allies, which did not participate in the initial fighting, there were around 500 Dutch soldiers – a sergeant and two corporals, 20 Europeans, 130 Mardijkers, 240 from Sabu, 60 from Solor, and 30 from Rote, in addition to volunteers from the company.
[13][14] Prior to the battle, large parts of Kupang's population fled the town, fearing the approaching army, with Dutch accounts noting the local VOC commander needing to convince their native allies into fighting.
[16] Da Costa's army camped at Penfui, a hillside to the east of Kupang, and constructed stone and earthen forts there.
Eventually, with the Topasses trapped in the final fortification, da Costa attempted to flee the battlefield, but was struck down from his horse by an assegai before he went far, and was beheaded.
[19][20] In 1769, Portuguese authorities on the island later shifted their headquarters from Lifau in the west to Dili in the east, due to both the Dutch and the Topasses.
[20][21] Dutch historian Herman Gerrit Schulte Nordholt [nl] remarked that though impressions of the battle as a turning point in Timorese history are an "exaggeration", the balance of power in the island shifted dramatically after the battle, and had da Costa achieved victory, Timor and the Solor archipelago might have remained Portuguese.
[12] Due to the Dutch victory, the Protestant church maintained its presence on Timor, though there were no immediate attempts to enforce the religion to the locals.