The Koreans, descended from Tungusic tribal peoples, are a distinct racial and cultural group. According to Korean legend, Tangun established Old Choson in NW Korea in 2333 B.C., and the Korean calendar enumerates the years from this date. Chinese sources assert that Ki-tze (Kija), a Shang dynasty refugee, founded a colony at Pyongyang in 1122 B.C., but the first Korean ruler recorded in contemporaneous records is Wiman, possibly a Chinese invader who overthrew Old Choson and established his rule in N Korea in 194 B.C. Chinese forces subsequently conquered (c.100 B.C.) the eastern half of the peninsula. Lolang, near modern Pyongyang, was the chief center of Chinese rule.
Koguryo, a native Korean kingdom, arose in the north on both sides of the Yalu River by the 1st cent. A.D.; tradition says it was founded in 37 B.C. By the 4th cent. A.D. it had conquered Lolang, and at its height under King Kwanggaet'o (r.391–413) occupied much of what is now Korea and NE China. In the 6th and 7th cent. the kingdom resisted several Chinese invasions. Meanwhile in the south, two main kingdoms emerged, Paekche (traditionally founded 18 B.C., but significant beginning c.A.D. 250) in the west and Silla (traditionally founded 57 B.C., but significant beginning c.A.D. 350) in the east. After forming an alliance with T'ang China, Silla conquered Paekche and Koguryo by 668, and then expelled the Chinese and unified much of the peninsula. Remnants of Koguryo formed the kingdom of Parhae (north of the Taedong River and largely in E Manchuria), which lasted until 926.
Under Silla's rule, Korea prospered and the arts flourished; Buddhism, which had entered Korea in the 4th cent., became dominant in this period. In 935 the Silla dynasty, which had been in decline for a century, was overthrown by Wang Kon, who had established (918) the Koryo dynasty (the name was selected as an abbreviated form of Koguryo and is the source of the name Korea). During the Koryo period, literature was cultivated, and although Buddhism remained the state religion, Confucianism—introduced from China during the Silla years and adapted to Korean customs—controlled the pattern of government. A coup in 1170 led to a period of military rule. In 1231, Mongol forces invaded from China, initiating a war that was waged intermittently for some 30 years. Peace came when Koryo accepted Mongol suzerainty, and a long period of Koryo-Mongol alliance followed. In 1392, Yi Songgye, a general who favored the Ming dynasty (which had replaced the Mongols in China), seized the throne and established the Choson dynasty.
The Choson (or Yi) dynasty, which was to rule until 1910, built a new capital at Hanseong (Seoul) and established Confucianism as the official religion. Early in the dynasty (15th cent.) printing with movable metal type, which had been developed two centuries earlier, became widely used, and the Korean alphabet was developed. The 1592 invasion by the Japanese shogun Hideyoshi was driven back by Choson and Ming forces, but only after six years of great devastation and suffering. Manchu invasions in the first half of the 17th cent. resulted in Korea being made (1637) a tributary state of the Manchu dynasty. Subsequent factional strife gave way, in the 18th cent., to economic prosperity and a cultural and intellectual renaissance. Korea limited its foreign contacts during this period and later resisted, longer than China or Japan, trade with the West, which led to its being called the Hermit Kingdom.
In 1876, Japan forced a commerical treaty with Korea, and to offset the Japanese influence, trade agreements were also concluded (1880s) with the United States and European nations. Japan's control was tightened after the First Sino-Japanese War (1894–95) and the Russo-Japanese War (1904–5), when Japanese troops moved through Korea to attack Manchuria. These troops were never withdrawn, and in 1905 Japan declared a virtual protectorate over Korea and in 1910 formally annexed the country. The Japanese instituted vast social and economic changes, building modern industries and railroads, but their rule (1910–45) was harsh and exploitative. Sporadic Korean attempts to overthrow the Japanese were unsuccessful, and after 1919 a provisional Korean government, under Syngman Rhee, was established at Shanghai, China.
In World War II, at the Cairo Conference (1943), the United States, Great Britain, and China promised Korea independence. At the end of the war Korea was arbitrarily divided into two zones as a temporary expedient; Soviet troops were north and Americans south of the line of lat. 38°N. The Soviet Union thwarted UN efforts to hold elections and reunite the country under one government. When relations between the Soviet Union and the United States worsened, trade between the two zones ceased; great economic hardship resulted, since the regions were economically interdependent, industry and trade being concentrated in the North and agriculture in the South.
In 1948 two separate regimes were formally established—the Republic of Korea in the South, and the Democratic People's Republic under Communist rule in the North. By mid-1949 all Soviet and American troops were withdrawn, and two rival Korean governments were in operation, each eager to unify the country under its own rule. In June, 1950, the North Korean army launched a surprise attack against South Korea, initiating the Korean War, and with it, severe hardship, loss of life, and enormous devastation.
After the war the boundary was stabilized along a line running from the Han estuary generally northeast across the 38th parallel to a point south of Kosong (Kuum-ni), with a "no-man's land" or demilitarized zone (DMZ), 1.24 mi (2 km) wide and occupying a total of 487 sq mi (1,261 sq km), on either side of the boundary. The western border in the ocean, though, was not defined, and fighting has occasionally occurred at sea. Throughout the 1950s and 60s an uneasy truce prevailed; thousands of soldiers were poised on each side of the demilitarized zone, and there were occasional shooting incidents. In 1971 negotiations between North and South Korea provided the first hope for peaceful reunification of the peninsula; in Nov., 1972, an agreement was reached for the establishment of joint machinery to work toward unification.
The countries met several times during the 1980s to discuss reunification, and in 1990 there were three meetings between the prime ministers of North and South Korea. These talks have yielded some results, such as the exchange of family visits organized in 1989. The problems blocking complete reunification, however, continue to be substantial. Two incidents of terrorism against South Korea were widely attributed to North Korea: a 1983 bombing that killed several members of the South Korean government, and the 1987 destruction of a South Korean airliner over the Thailand-Myanmar border. In 1996, North Korea said it would cease to recognize the demilitarized zone between the two Koreas, and North Korean troops made incursions into the zone. In 1999 a North Korean torpedo boat was sunk by a South Korean vessel in South Korean waters following a gun battle, and another deadly naval confrontation following a North Korean incursion in 2002.
In early 2000, however, the North engaged in talks with a number of Western nations, seeking diplomatic relations, and South and North agreed to a presidential summit in Pyongyang. The historic and cordial meeting produced an accord that called for working toward reunification (though without specifying how) and for permitting visits between families long divided as a result of the war. Given the emotional appeal of reunification, it is likely that the North-South dialogue will continue, despite the problems involved; however, the tensions that developed in late 2002 have, for the time being, derailed any significant further reunification talks. Economic contacts continued to expand, however, and South Korea became a significant trade partner for the North. The North also received substantial aid from the South.
In 2007 a rail crossing through the DMZ was symbolically reopened when two trains made test runs on the rebuilt track; regular rail service, over a short line, began late in the year. A second North-South presidential summit in Pyongyang occurred in Aug., 2007; both leaders called for negotiations on a permanent peace treaty to replace the armistice that ended the Korean War. Relations between the two nations subsequently soured, as a result of the election (2007) of Lee Myung Bak as president of South Korea and the sinking (2010) of a South Korean naval vessel by the North. Most joint projects came to an end, and trade between the two nations greatly decreased by 2010. Many U.S. troops still remain in the South, though their numbers have decreased since the 1960s and the number of U.S. bases has been greatly reduced.