his own eyes the extent and condition of his new domain." The Taiwanese aboriginal tribes who were previously allied with the Dutch against the Chinese during the Guo Huaiyi rebellion in 1652 turned against the Dutch during the siege and defected to Zheng's Chinese forces. The aboriginals of Sincan defected to Zheng after he offered them amnesty. The Sincan aboriginals then proceeded to work for the Chinese and behead Dutch people in executions. The frontier aboriginals in the mountains and plains also surrendered and defected to the Chinese on 17 May 1661, celebrating their freedom from compulsory education under the Dutch rule by hunting down Dutch people and beheading them and trashing their Christian school textbooks. In April 1662, Zheng sent a message to Manila demanding annual tribute. Sabiniano Manrique de Lara, the Spanish Governor-General of the Philippines, rejected the request and strengthened defenses in anticipation of an attack. The non-Christian Chinese population was dispersed. Zheng declared his intention to conquer the Philippines in retaliation for the Spanish mistreatment of the Chinese settlers there, which was also the reason he used for attacking Dutch Taiwan. Tensions eased after Zheng Chenggong died on 23 June, four months after the end of the siege of Fort Zeelandia. It is uncertain how he died and causes range from malaria to pneumonia to dysentery. One version of events say he died in a fit of madness when his officers refused his orders to execute his son, Zheng Jing, who had an affair with his wet nurse and conceived a child with her. Zheng became a legendary figure in folk tales and his image as a Ming loyalist was honored even by the Kangxi Emperor of the Qing dynasty, who removed his name from the "sea banditry" category and labelled him a valiant loyalist to a deposed dynasty. Chinese nationalists in the 20th century invoked Zheng Chenggong for his patriotism and political loyalty against Qing and foreign influence. Dutch ships continued to come into conflict with Zheng forces in the 17th century and in 1663, the Dutch officially became allies of the Qing dynasty against the Zheng forces. The Dutch looted a Buddhist complex on the Zhoushan islands in 1665 and slaughtered its monks. The Dutch held out at Keelung until 1668 when their presence became untenable due to hostile natives and withdrew from Taiwan completely. The Zheng navy executed 34 Dutch sailors and drowned