Ancient China developed between the Yellow River (Huang He) and the Yangtze River. These rivers dominated Chinese civilization and flowed west to east, with the Yellow River known for its fertile silt but also destructive flooding. Ancient China dates from 1523 BC to 221 BC. China believed itself isolated at the center of the world, surrounded by mountain ranges and the Gobi Desert. Chinese political history was characterized by dynastic cycles, where the Mandate of Heaven justified the rise and fall of ruling dynasties, transferring power when a dynasty no longer satisfied the people and gods.