Quanzhou, formerly known as Chinchew, is a prefecture-level city beside the Taiwan Strait in Fujian Province, People's Republic of China. It is Fujian's largest metropolitan region, with an area of 11,245 square kilometers and, as of the 2010 census, a population of 8,128,530. Its built-up area is home to 6,107,475 inhabitants, encompassing the Licheng, Fengze, and Luojiang urban districts; Jinjiang, Nan'an, and Shishi cities; Hui'an County; and the Quanzhou District for Taiwanese Investment. Quanzhou was China's 12th-largest extended metropolitan area in 2010. Quanzhou was China's major port for foreign traders, who knew it as Zaiton, during the 11th through 14th centuries. It was visited by both Marco Polo and Ibn Battuta; both travelers praised it as one of the most prosperous and glorious cities in the world. It was the naval base from which the Mongol attacks on Japan and Java were primarily launched and a cosmopolitan center with Buddhist and Hindu temples, Islamic mosques, and Christian churches, including a Catholic cathedral and Franciscan monasteries. A failed revolt prompted a massacre of the city's foreign communities in 1357.