Spanish colonial outpost on the northern tip of Taiwan ("Isla Hermosa"), founded from Manila to protect trade routes and counter Dutch expansion; Dominican and Franciscan missionaries converted roughly 5,000 indigenous people during its short existence.
A 1642 Dutch assault (after a repelled 1641 attempt) took Fort San Salvador after six days of fighting, once Spanish authorities in Manila had already recalled troops for operations in the Philippines; Governor-General Sebastián Hurtado de Corcuera was later imprisoned over the loss.
Polity-specific: the standard scholarly monograph on this exact colony and date range, verified on Open Library.