Evidence of inhabitants in Korea from as early as 4000 BC exists in Korea. In the 1st century BC three kingdoms emerged, namely Shilla, Koguryo and Paekche. All three kingdoms were heavily influenced by China, and Buddhism was introduced to Koguryo in 372. Various alliances were formed either with or against the Chinese until 660 when Shilla allied with China to overthrow Paekche.

In 1231 the Mongols invaded Korea and controlled it for 150 years. In 1392 a Korean general was sent to China to campaign against the Ming rulers. Instead, he allied himself with the Chinese, returned to overthrow the Korean king, and setup his own dynasty.

The ruler of the Chosun Dynasty adopted Confucianism as the country's official religion. It was during this period that the Korean alphabet was invented. This period also had its share of external problems, suffering invasions by the Japanese (1592-1598) and the Manchus (1627-1636).

With the arrival of Japanese and Western traders in the 19th century, the Korean rulers tried to prevent the opening of the country to foreign trade by closing the borders, earning Korea its nickname of the Hermit Kingdom.

Beginning in 1876, the Japanese forced a series of agreements on Korea, leading to Japan's eventual annexation. During the Russo-Japanese War (1904-1905), Japanese forces moved onto the peninsula, despite Korean declarations of neutrality. The signing of the Japan-Korea Protection Treaty in 1905 gave Japan virtual control over Korea, and in 1910 a Korean royal proclamation announced the annexation by Japan.