Gojoseon, also called Joseon, was the first kingdom on the Korean Peninsula. According to Korean mythology, the kingdom was established by the legendary king Dangun. Gojoseon possessed the most advanced culture in the Korean Peninsula at the time and was an important marker in the progression towards the more centralized states of later periods. The addition of Go, meaning "ancient", is used in historiography to distinguish the kingdom from the Joseon dynasty, founded in 1392 CE.

Dangun or Tangun, also known as Dangun Wanggeom, was the legendary founder and god-king of Gojoseon, the first Korean kingdom, around present-day Liaoning province in Northeast China and the northern part of the Korean Peninsula. He is said to be the "grandson of heaven" and "son of a bear", and to have founded the kingdom in 2333 BC. The earliest recorded version of the Dangun legend appears in the 13th-century Samguk Yusa, which cites China's Book of Wei and Korea's lost historical record Gogi. However, it has been confirmed that there is no relevant record in China's Book of Wei. There are around seventeen religious groups that focus on the worship of Dangun.