Siege of Fort Zeelandia
He Bin, who was working for the Dutch East India Company, fled to Koxinga's base in Xiamen and provided Koxinga with a map of Taiwan. The Dutch had established a post at Tayoan, that had two forts.  The first was Fort Zeelandia at the entrance to the bay at Tayoan which was the main Dutch settlement. The second was Fort Provintia also located at the bay. Frederick Coyett, the governor of Taiwan was at Fort Zeelandia with 1,800 men. Fort Provintia had 500 men.