Jiangnan, also romanized as Kiangnan, Chiang-nan, and Jiang Nan, is a geographic area in China referring to lands immediately to the south of the lower reaches of the Yangtze River, including the southern part of its delta. The region encompasses the city of Shanghai, the southern part of Jiangsu Province, the southeastern part of Anhui Province, the northern part of Jiangxi Province and the northern part of Zhejiang Province. The most important cities in the area include Anqing, Changzhou, Hangzhou, Nanjing, Ningbo, Shaoxing, Suzhou, Wuxi, Wenzhou, Yangzhou and Zhenjiang. Jiangnan has long been regarded as one of the most prosperous regions in China due to its wealth in trade and very high human development. Most people of the region speak Wu Chinese dialects as their native languages. The name Jiangnan is the atonal pinyin romanization of the Standard Mandarin pronunciation of the Chinese name , meaning "[Lands] South of the [Yangtze] River". (Although is now the common Chinese word for any large river, it was previously used in Ancient Chinese as the specific name of the Yangtze, with other use spreading from there.) Using other romanization systems, the same Chinese name was also written Chiang-nan, Chiangnan, Kiang-nan, Kiangnan, and Keang-nan in English and other European languages. The earliest archaeological evidences were of the Majiabang and of the Hemudu cultures. The later Liangzhu culture, from around 2600–2000 BC, created complex and beautiful jade artifacts. Their economy was based on rice cultivation, fishing and constructed houses on stilts over rivers or lakes. During the Zhou dynasty, the Wu and Baiyue peoples inhabited the area with heavy aquaculture and stilt houses, but became increasingly sinicized through contact with northern Chinese states. They adopted the Chinese writing system and created excellent bronze swords. The Chu state from the west (in Hubei) expanded into this area and defeated the Yue state. After Chu was conquered by the Qin state, China was unified.