Hunan is a province in southern China located in the middle reaches of the Yangze River, occupying some of China's richest land. Hunan entered the history of China around 350 BC, when under the kings of the Zhou dynasty it became part of the State of Chu. Its population increased fivefold between the 8th and 11th centuries because of its prosperous agriculture and massive immigration. Several prominent Communist leaders including Mao Zedong and Hu Yaobang originate from Hunan.