Siege of Fort Zeelandia
On July 23, the two sides fought as the Dutch ships tried to enter the fort. After a while, the Dutch ships had to retreat with two ships lost, three small vessels captured, and about a hundred casualties. The Dutch tried to break the siege again in October, but were beaten back by Koxinga's army. This victory, coupled with news of low morale among the garrison from deserted German mercenaries, convinced Koxinga to launched an assault in December.