This article examines the changes undergone by the Council of Nobles (Hwabaek hoeui) from the early ancient to Unified Silla period. The Council of Nobles was a conference where matters of national importance were discussed, and was divided-depending on where the meeting took place and who presided over the proceedings-into the Council of the Southern Hall (Namdang hoeui) and the Council for Political Affairs (Jeongsa-dang). The Council of the Southern Hall referred to a meeting where the sovereign discussed matters of national importance with his vassals, and the Council for Political Affairs referred to meetings supervised by administrators such as the Sangdaedeung. The former represented the ultimate level of decision-making in the administration of state affairs during Silla's early ancient period. The Council for Political Affairs was run by officials dispatched by the yukbu to carry out the decisions made at the Council of Southern Hall, with one government official delegated to handle national affairs presiding. With the dismantling of the yukbu system in the 530s, the responsibilities of the Council of the Southern Hall changed to that of assisting and advising the sovereign at the ultimate decision-making level while he administered state affairs. The Sangdaedeung presided over the Council for Political Affairs, which had at its core members of the Daedeung during the middle ancient period. During this period, matters of national importance were discussed primarily at the Council for Political Affairs, where an administrator such as the Sangdaedeung submitted resolutions to the sovereign, who would accept them and order their execution in the form of instructions or royal commands. The Daedeung had to personally carry out the instructions or royal commands until the reign of King jinheung, since the reorganization of the centralized administrative office was not completed until that time.
During the Unified Silla period, the Sang(dae)jaesang replaced the Sangdaedeung as the official presiding over the Council for Political Affairs. After matters of national importance were discussed at this council, the monarch would approve decisions made by the council and the central administrative office would execute them, showing that decision-making and implementation became distinct functions carried out by different organs.
So that administration of state affairs could be carried out efficiently, the ranks of the Jaesang were populated with many ministers from the administrative office. The sovereign was only able to restrain the power of the Jaesang during the Unified Silla period through the power of ministerial appointment and ultimate decision-making. However, the influence wielded by the high-ranking officials that held the position of Jaesang also made it difficult for the monarch to oppose decisions made by the Council of Jaesangs that were legitimate. This indicates that that a balance of powers existed between the sovereign and the Jaesang during the Unified Silla period. While relative political stability was achieved via this system of checks and balances, the breakdown of this system in the Later Silla period led to political instability.