Fēngjiàn was a governance system in Ancient China and Imperial China, whose social structure formed a decentralized system of confederation-like government. The ruling class consisted of the Son of Heaven and aristocracy, and the lower class consisted of commoners categorized into four occupations. Elite bonds through affinal relations and submission to the overlordship of the king date back to the Shang dynasty, but it was the Western Zhou dynasty when the Zhou kings enfeoffed their clan relatives and fellow warriors as vassals. Through the fengjian system, the king would allocate an area of land to a noble, establishing him as the ruler of that region and allowing his title and fief to be legitimately inherited by his descendants. This created large numbers of local autonomous dynastic domains.