The Spanish attempt to establish a foothold on the island of Taiwan began relatively late (1626), remained confined to a small area in the north, and lasted only sixteen years, ending in 1642. Beyond the pressures of rivalry with the Dutch —who had already established themselves in the island’s southwest two years earlier— the failure of the Spanish colonial project in Taiwan was largely due to sustained resistance from Indigenous peoples. After establishing two fortified positions with their military garrisons at Keelung (1626) and Tamsui (1628), almost all Spanish efforts to penetrate the interior or reach the eastern coast in search of natural riches, food supplies, labor, and potential converts to the Catholic faith were met with unfriendly reactions from native communities. Repeated acts of violence against Spanish personnel are recorded in contemporary sources. The most significant of these incidents, both in scale and consequence, occurred in April 1636 near Tamsui. Approximately 300 indigenous warriors ambushed a Spanish expedition of around sixty soldiers, laborers, and missionaries, killing roughly half of them. The uprising then escalated with an assault on the Santo Domingo fort itself. News of these events caused alarm in Manila, the seat of the Captaincy General of the Philippines, which exercised jurisdiction over the Spanish outposts in Taiwan. In response, governor-general Corcuera ordered punitive actions against the natives of Tamsui, followed by the abandonment and burning of the fortress and the retreat of the garrison to Keelung. According to several interpretations, this episode also marked the moment when Spanish authorities realized that their venture in Taiwan was ultimately doomed to failure.