After being ousted from Taiwan, the Dutch allied with the new Qing dynasty in China against the Zheng regime in Taiwan. Following some skirmishes the Dutch retook the northern fortress at Keelung in 1664. Zheng Jing sent troops to dislodge the Dutch, but they were unsuccessful. The Dutch held out at Keelung until 1668, when aborigine resistance, and the lack of progress in retaking any other parts of the island persuaded the colonial authorities to abandon this final stronghold and withdraw from Taiwan altogether.