Samguk yusa in the context of "Il-yeon"

The Lower Paleolithic era on the Korean Peninsula and in Manchuria began roughly half a million years ago. The earliest known Korean pottery dates to around 8000 BC and the Neolithic period began thereafter, followed by the Bronze Age by 2000 BC, and the Iron Age around 700 BC. The Paleolithic people are likely not the direct ancestors of the present Korean people, but their direct ancestors are thought to be the Neolithic People of about 2000 BC.

According to the mythic account recounted in the Samguk yusa (1281), the Gojoseon kingdom was founded in northern Korea and southern Manchuria in 2333 BC. The first written historical record on Gojoseon can be found from the text Guanzi. The Jin state was formed in southern Korea by the 3rd century BC. In the late 2nd century BC, Gojoseon eventually fell to the Han dynasty of China, which led to succeeding warring states, the Proto–Three Kingdoms period.

Old Chosŏn, also known as Gojoseon (Korean: 고조선; Hanja: 古朝鮮; RR: Gojoseon; MR: Kojosŏn) and its contemporary name Joseon (Korean: 조선; Hanja: 朝鮮; RR: Joseon; MR: Chosŏn), was the first kingdom on the Korean Peninsula. According to Korean mythology, the kingdom was established by the legendary king Tan'gun. Old Chosŏn 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 (고; 古), meaning "old" or "ancient", is used in historiography to distinguish the kingdom from the Joseon dynasty, founded in 1392 CE.

According to the Memorabilia of the Three Kingdoms, Old Chosŏn was established in 2333 BCE by Tan'gun, who was said to be born from the heavenly prince Hwanung and a bear-woman, Ungnyeo. While Tan'gun is a mythological figure of whose existence no concrete evidence has been found, some interpret his legend as reflections of the sociocultural situations involving the kingdom's early development. Regardless, the account of Tan'gun has played an important role in the development of Korean identity. Today, the founding date of Old Chosŏn is officially celebrated as National Foundation Day in North and South Korea.

Korean mythology (Korean: 한국 신화; Hanja: 韓國神話) is the group of myths told by historical and modern Koreans. There are two types: the written, literary mythology in traditional histories, mostly about the founding monarchs of various historical kingdoms, and the much larger and more diverse oral mythology, mostly narratives sung by shamans or priestesses (mansin) in rituals invoking the gods and which are still considered sacred today.

The historicized state-foundation myths representing the bulk of the literary mythology are preserved in Hanja literary works such as Samguk sagi and Samguk yusa. One state's foundation myth, that of the first Korean kingdom of Gojoseon by legendary king Dangun, has become the founding myth of the whole Korean nation. State-foundation myths are further divided into northern, such as that of the kingdom of Goguryeo and its founder Jumong, where the founder is the son of a celestial male figure and an earthly female figure, and southern, such as that of the kingdom of Silla and its founder Hyeokgeose, where the founder begins as an object descended from the heavens, and himself marries an earthly woman. Other literary myths include the origin myths of family lineages recorded in genealogies.

Tan'gun (Korean: 단군; Hanja: 檀君; RR: Dangun; pronounced [tan.ɡun]), also known as Tan'gun Wanggŏm (단군왕검; 檀君王儉; [tan.ɡun waŋ.ɡʌm]), was the legendary founder and first king of Gojoseon, the first Korean kingdom. He founded the first kingdom around the northern part of the Korean Peninsula. He is said to be the "grandson of heaven", "son of a bear", and to have founded the first kingdom in 2333 BC.

The earliest recorded version of the Tan'gun legend appears in the 13th-century Samguk yusa, which purportedly cites Korea's lost historical record, Gogi (고기; 古記; lit. 'Ancient Record') and China's Book of Wei. However, there are no records related to Tan'gun in the current surviving version of the Book of Wei.

The Silla–Goguryeo and Paekche–Kaya–Wa War (Korean: 나여–제야왜 전쟁; Hanja: 羅麗・濟倻倭 戰爭; RR: Nayeo–Jeyawae Jeonjaeng; MR: Nayŏ–Cheyawae Chŏnjaëng) was a series of conflicts that spanned for 40 years from the mid 4th century to the early 5th century between the Silla–Goguryeo alliance and the Paekche–Kaya–Wa alliance according to the Samguk sagi, Samguk yusa, Nihon Shoki, and inscriptions found in the Gwanggaeto Stele.

It was the first and only time where all four nations of Korea (Goguryeo–Silla–Paekche–Kaya) were involved in a single war, and Wa (Japan)'s first international conflict prior to the introduction of the Yamato Kingship and the following Battle of Baekgang that came after.