Samguk sagi in the context of Injong of Goryeo

Onjo (Korean: 온조; Hanja: 溫祚; ?–28, reigned c. 18 BC – AD 28) was the founding monarch of Paekche, one of the Three Kingdoms of Korea. According to the Samguk sagi, he founded the royal family of Paekche.

37°31′50.25″N 127°7′0.62″E / 37.5306250°N 127.1168389°E / 37.5306250; 127.1168389

Wiryeseong (Korean: 위례성; Hanja: 慰禮城) was the name of two early capitals of Baekje, one of the Three Kingdoms of Korea. Both are believed to have been in the modern-day Seoul area. According to the Samguk sagi (the oldest surviving Korean history books, written in the 12th century), Onjo, the son of Goguryeo's founder Jumong, founded the nation of Sipje (십제, 十濟; later became Baekje) on Wiryeseong in 18 BC, while his elder brother Biryu established himself in Michuhol (미추홀; 彌鄒忽) further to the west. The location of Michuhol is usually believed to be present-day Incheon.

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.

The Peninsular Japonic languages are postulated now-extinct Japonic languages reflected in ancient placenames and glosses from central and southern parts of the Korean Peninsula.Most linguists believe that Japonic arrived in the Japanese archipelago from the Korean peninsula during the first millennium BCE.The placename evidence suggests that Japonic languages were still spoken in parts of the peninsula for several centuries before being replaced by the spread of Korean.

The most-cited evidence comes from chapter 37 of the Samguk sagi (compiled in 1145), which contains a list of pronunciations and meanings of placenames in the former kingdom of Goguryeo. As the pronunciations are given using Chinese characters, they are difficult to interpret, but several of those from central Korea, in the area south of the Han River captured from Baekje in the 5th century, seem to correspond to Japonic words. Scholars differ on whether they represent the language of Goguryeo or the people that it conquered.

Usan-guk or the State of Usan (Korean: 우산국; Hanja: 于山國) was a statelet that occupied the island Ulleungdo and several adjacent islands in Korea during the Three Kingdoms period. According to the Samguk sagi, it was conquered by the Silla general Kim Isabu in 512. He is said to have used wooden lions or tigers to intimidate the residents into surrendering. It has been written that the alias of Usan-guk is Ulleung-do. Usan-guk rarely entered into historical records, but appears to have continued a largely autonomous existence until its loss of independence to Goryeo in 930.

Michu was the thirteenth ruler of the Korean state of Silla (r. 262–284). He was the first king of the Kim clan to sit on the Silla throne; this clan would hold the throne for most of Silla's later history. He was the son of Gudo, a leading Silla general, and the sixth-generation descendant of the clan founder Kim Alji.

During Michu's reign, the Samguk sagi reports numerous attacks from Baekje, and does not mention any contact with the other neighboring states.

Gwangju (Korean: 광주; Korean: [kwaŋ.dʑu] ), formerly romanized as Kwangju, is South Korea's sixth-largest metropolis. It is a designated metropolitan city under the direct control of the central government's Home Minister. The city was also the capital of South Jeolla Province until the provincial office moved to the southern village of Namak in Muan County in 2005 because Gwangju was promoted to a metropolitan city and was independent of South Jeolla Province.

Its name is composed of the words gwang (Korean: 광; Hanja: 光) meaning "light" and ju (주; 州) meaning "province". Gwangju was historically recorded as Muju (무주; 武州), in which "Silla merged all of the land to establish the provinces of Gwangju, Ungju, Jeonju, Muju and various counties, plus the southern boundary of Goguryeo and the ancient territories of Silla" in the Samguk sagi. In the heart of the agricultural Jeolla region, the city is also famous for its rich and diverse cuisine.

Muryeong (461/462–523) was the 25th king of Baekje, one of the Three Kingdoms of Korea, reigning from 501 to 523. During his reign, Baekje remained allied with Silla against Goguryeo, and expanded its relationships with China and Japan. According to Samguk sagi, his height was recorded as 8 feet (190 cm).

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.