In the hierarchical social order, the emperor was at the apex of Han society and government. However the emperor was often a minor, ruled over by a regent such as the empress dowager or one of her male relatives. Ranked immediately below the emperor were the kings who were of the same Liu family clan. The rest of society, including nobles lower than kings and all commoners excluding slaves belonged to one of twenty ranks (ershi gongcheng 二十公乘).