population decline, Zheng Jing also promoted migration to Taiwan. Between 1665 and 1669 a large number of Fujianese moved to Taiwan under Zheng rule. In a few years, some 9,000 Chinese were brought to Taiwan by Zheng Jing. The Qing dynasty enacted a sea-ban on coastal China to starve out the Zheng forces. In 1663, the writer Xia Lin who lived in Xiamen testified that the Zhengs were short on supplies and the people suffered tremendous hardship due to the Qing sea ban (haijin) policy. After Zheng forces retreated completely from the coast of Fujian in 1669, the Qing started relaxing restrictions on maritime trade. Due to the sea ban policy, which saw the relocation of all southern coastal towns and ports that had been subject to Zheng raids, migration occurred from these areas to Taiwan. About 1,000 previous Ming government officials moved to Taiwan fleeing Qing persecution. From June to August 1663, Duke Huang Wu of Haicheng and commander Shi Lang of Tongan urged the Qing court to take Xiamen, and made plans for an attack in October. The Dutch too had attacked Zheng ships in Xiamen but failed to take the town. In August the Dutch contacted Qing authorities in Fujian to propose a joint expedition against Zheng Taiwan. The message did not reach the Qing court until 7 January 1663 and it took another four months for a reply. The Kangxi Emperor granted the Dutch permission to set up inland trading posts but declined the proposal for a joint expedition. The Dutch did however assist the Qing in naval combat against the Zheng fleet in October 1663, resulting in the capture of Zheng bases in Xiamen and Kinmen in November. The Zheng admiral Zhou Quanbin surrendered on 20 November. The remaining Zheng forces fled southward and completely evacuated from the mainland coast in the spring of 1664. Qing-Dutch forces attempted to invade Taiwan twice in December 1664. On both occasions Admiral Shi Lang turned back his ships due to adverse weather. Shi Lang tried to attack Taiwan again in 1666 but turned back due to a storm. The Dutch continued to attack Zheng ships from time to time, disrupting trade, and occupied Keelung until 1668, but they were unable to take back the island. Their position at sea was gradually taken over by Great Britain. On 10 September 1670, a representative from the British East India Company