The Bronze Age began around 1,500 to 2,000 B.C. in present-day Mongolia and on the peninsula. As this civilization began to form, numerous tribes appeared in the Liaoning region of Manchuria and in northwestern Korea. These tribes were ruled by leaders, whom Dangun, the founder of the Korean people, later united to establish Gojoseon (2333 B.C.). The founding date is a testament to the longevity of Korea's history. This heritage is also a source of pride for Koreans and their strength to persevere in times of adversity.