The history of China goes back to the ancient civilization – one of the world's earliest – that flourished in the fertile basin of the Yellow River in the North China Plain. For millennia, China's political system was based on hereditary monarchies, known as dynasties, beginning with the semi-mythological Xia of the Yellow River basin (c. 2000 BCE). Since 221 BCE, when the Qin Dynasty first conquered several states to form a Chinese empire, the country has expanded, fractured and been reformed numerous times. The Republic of China (ROC) overthrew the last dynasty in 1911, and ruled the Chinese mainland until 1949. After the defeat of the Empire of Japan in World War II, the Communist Party defeated the nationalist Kuomintang in mainland China and established the People's Republic of China in Beijing on 1 October 1949, while the Kuomintang relocated the ROC government to its present capital of Taipei.