Traditional Thai historians considered the foundation of the Sukhothai Kingdom as the beginning of the nation. In the political and administrative system at that time the King ruled the State as the citizens’ father, the so called “Po Khun”. This system was used to rule the State for a century. The first reform of the political and administrative system began during the reign of King Ramatibodi I of the Ayuttaya Kingdom, B.E. 1857-1912 (1351-1369) in order to respond to the expanded power of the Kingdom. The four pillars of state (Cha-tu-sa-dom) propagated from the Indian political system were adopted instead of the “Po Khun” system. King Trailokanat ofAyuthaya, B.C.1991-2031 (1448-1488) reformed the Siamese bureaucracy once again by separating civil and military officials. “Sa-mu-ha-na-yok” was the Head of the Civil Office which took responsibility for civil duties, and “Sa-mu-ha-ka-la-hom” was the Head of the Military Office responsible for military duties. In his reign, the hierarchies of the nobility were first codified. Officials had titular ranks and feudal ranks called “Sakdi na”. He also adopted a palatinate law in order to re-categorize the cities of Ayutthaya by class, the hierarchy of cities ranging from the Inner Cities and Outer Cities to Colonies.