Ancient China was shaped by its geography. Civilization developed along two major river systems, the Chang Jiang and Huang He rivers, which provided fertile land for farming. China was also isolated by surrounding deserts and mountains. The first dynasty, the Shang, ruled in the 1700s BC and developed one of the world's earliest forms of writing. The Zhou dynasty overthrew the Shang in 1027 BC and introduced new political concepts. During the Warring States period, powerful states battled for dominance as Chinese philosophy developed, including Confucianism, Daoism, and Legalism. In 221 BC, the Qin unified China and standardized the written language, but fell shortly after. The long-