Bronze Age artifacts in Korea indicate a stratified society. The bronze daggers and mirrors would have been the possessions of only a privileged few, whose authority was symbolized by their ownership of the items. Some Dolmen (stone cyst tombs) have capstones weighing up to seventy tons, suggesting that the persons in the tombs had the power to command many, many people. Dolmen are found in clusters of as many as one hundred, built in an orderly fashion indicating a lineage of stratified society.
Bronze Age people lived in tribal states or small walled-town states. These territories were not extensive; they consisted of narrow plains for farming. The people built earthen fortifications on hillside plateaus. These walled-town states were the earliest form of state structure to exist in Korea and represent the origins of Korean political culture. Societies with articulated political structures began to develop around the walled-town states. By about the fourth century BC, these states had developed to the point that they were known in China.
Modern Korean people trace their origins to the founding of the Gojoseon (ancient Korean) state. To research the establishment of Gojoseon, one must look back over four thousand years into the clouded past where history and myth begin to blend. The legendary beginning date of Gojoseon depends upon the source used. The myth "Tan-gun" sets the date at 2333 BC, while the myth "Ki-ja" sets the date at 1122 BC. The actual date is unknown. The Gojoseon patriarch was Dangun Wanggom. Gojoseon first developed with the Liaoning district as its center and gradually rose as a center of the East. The Gojoseon ended in 57 BC with the traditional beginning of the Three Kingdoms Era.