The Early Iron Age in Korean Peninsula is the period when the usage of ironware was initiated based upon the already developed Bronze culture, The center of this period dates back to the second and third century B, C. At the time, in Korean peninsula, numerous polities were established upon the early iron Age culture. In this article, Uprak(邑落集團) represents these polities of the Early Iron Age, In order to shed lights on these polities' characteristics, this article examines the polity ruler's authoritative foundation and its changes over time, hence, suggesting the important differences between the polities of the Early Iron Age and the three Han called Sam-Han. The rulers of Upraks in the Early Iron Age were religious specialists whose authorities enabled them to achieve a significant status in politics, military affairs and economy. The examples of such powerful Uprak rulers are Sura of Gaya, Talhae of Shilla, and Jumong, of Koguryeo. According to documentary records, Jumong was described as a transcendent being that can control weathers on his will. Also, Suro and Talhae had a supernatural power to transform themselves into animals. And some rulers of Upraks in Koguryeo wore shaman costumes during rituals and ceremonies; these costumes were decorated with birds feather, hemp cloth or sea weeds, indicating the fact that the Uprak rulers were magic-religious specialists. According to archeological findings, the rulers of Upraks in the south-western part of the Korean Peninsula used various kinds of ritual tools mostly made of bronze. The ritual tools such as bronze mirror, bronze bell, rattle or cymbals-shaped bronze were believed to present supernatural abilities to the religious specialists for example, the magic powers to expel the ghosts and bring in super spirits or gods by generating lights and sounds. Also, with their advanced skills in bronze crafting, people in the Early Iron Age made images of agricultural gods, ancestor gods, or guardians and worship them. The most important duty as a religious specialist is to hold rituals and ceremonies to pray for the success in agriculture. Such agricultural rituals were related to the idea of worshiping ancestors because they believed that the success and failure of crop production was controlled by their ancestor spirits. Thus, after the death of a prominent Uprak ruler, people buried his various ritual tools in his tomb, and the tomb was used as an important ritual spot. In such context, the ritual and ceremony in the Early Iron Age functioned as important mechanism to bind Uprak members into a group. Since the late second century B.C., the polities were unified by region and emerged into more enlarged polities;Goguryeo on the Aprok and Hon River area, and Sam-Han 54 So-Guk(小國) in the south central part of the peninsula. During this transitional time, the rulers of Upraks were relieved of their role as a religious specialist; and their religious activities were entrusted to other religious specialists who nearly had responsibilities as sociopolitical rulers. From the first century A.D., the rulers of Sam-Han So-Guk reigned with his strong economic abilities and political powers with iron arms, Their authority as religious specialists was limited and fade away. Also, the essential ritual tools such as drums and rattles were positioned at Sodo(蘇塗). a divine territory; and the traditional religious activities held by magic-religious specialists were continued at Sodo, In Guk-up(國邑) area, center of So-Guk, new religious specialist called Chun-gun(天君) were appointed and performed worship ceremony of Chun-Shin, a god of heaven, who had superior position to the ancestor spirits of individual Uprak group.