Battle of Penfui
1749 CE.
Shown on the map at -10.164°, 123.662°.
The Battle of Penfui took place on 9 November 1749 in the hillside of Penfui, near modern Kupang. A large Topass army was defeated by a numerically inferior Dutch East India Company force following the withdrawal of the former's Timorese allies from the battlefield, resulting in the death of the Topass leader Gaspar da Costa. Following the battle, both Topass and Portuguese influence on Timor declined, eventually leading to the formation of a boundary between Dutch and Portuguese Timor which precipitated into the modern border between West Timor and East Timor.
Text from the Wikipedia article Battle of Penfui, licensed CC BY-SA 4.0.