Shamian Island was an important port for Guangzhou's foreign trade from the Song to the Qing dynasty. From the 18th to the mid 19th century, the foreigners lived and did business in a row of houses known as the Thirteen Factories, on the banks of the Pearl River to the east the present Shamian, which was then an anchorage for thousands of boat people. In 1859, Great Britain and France dug an artificial river (now called Shajichong) to the north, making it an island. Since then, Shamian became a strategic point for city defense during the First and Second Opium Wars. The British captured the Shamian Fort in the Canton River operations in March 1841 during the First Opium War. In the 1847 expedition to Canton, they seized the Shamian batteries along with the rest of the forts guarding the city. In the first armed conflict of the Second Opium War, the British recaptured the forts in 1856.