After the fall of the Mongols in China, Koreans were divided regarding the nature of their relationship with the Ming dynasty. In the 1380s, Yi Seong-gye and his fellow general Choe Yeong won fame for themselves when they defeated Japanese pirates who were raiding Korea. When the Ming dynasty attempted to annex Korean territory, Choe Yeong declared himself in opposition to the Ming and advised an invasion of China’s Liaodong Peninsula. Yi Seong-gye was chosen to lead the army but instead took the opportunity to seize Korea’s capital and gain control of the government in 1388. In 1392, after ruling for four years through puppet kings, Yi Seong-gye proclaimed himself the head of a new dynasty, the Joseon, named for an earlier Korean dynasty. Ruling as King Taejo, he declared himself a vassal of the far more powerful Ming dynasty and established friendly relations with China. Taejo embraced Confucian principles, which, unlike Buddhism, focus on the maintenance of the family and of social hierarchies instead of the well-being of the individual. Korean society was divided into rigidly defined classes. At the top was a ruling class of civil bureaucrats and military officials called the yangban, who ruled the country along with the king. Membership in this class depended on doing well on the imperial exams, which were based on knowledge of the Confucian classics, like similar exams in China. As in China, wealthy families and nobility of the former dynasty dominated the exams, because only the men in these families had the time and money to acquire the education necessary to do well. Membership in a yangban family also conferred the right to serve on local ruling councils and thus control their affairs. Eventually, membership in the yangban became hereditary when only the sons of these families were allowed to take the imperial exams. The yangban were supported by the labor of the sangmin, indentured servants who worked the land. Unlike the yangban, the seonbi were scholarly, highly educated men who devoted themselves to lives of study and served the public without financial reward. They did not covet riches and preferred scholarly pursuits, believing their role was to serve as moral exemplars for the rest of society. They valued integrity above all else and served as advocates of the common people even if that meant risking the displeasure of the king. Even though they came from the same class as the yangban, their lack of interest in attaining wealth and power set them apart. The love of study and learning that characterized the seonbi flourished in the reign of King Sejong, the fourth king of Korea. In 1442, Korean scholars developed a device to accurately gauge rainfall. Scholars also developed a means of measuring the direction and velocity of the wind. An astronomical observatory was constructed, and a variety of sundials and water clocks were invented to measure time (Figure 2.22). Triangulation devices and surveying rods were used to measure the elevation of land. Sejong recruited scholars from the institution of research he had founded, known as the Hall of Worthies, to help him develop hangul, an alphabet that could capture the sounds of Korean speech. Hangul, which Sejong introduced in 1446, was intended to be used by common people instead of the Chinese characters with which the elite yangban wrote. Figure 2.22 This fifteenth-century celestial globe, used to make astronomical observations, was invented by Jang Yeong-Sil during the reign of Korea’s King Sejong. (credit: “Korean armillary sphere” by Wikimachine/Wikimedia Commons, Public Domain) After the reign of Sejong, the Joseon dynasty encountered numerous difficulties. In 1592 and again in 1597, Japan invaded Korea. In the following century, the Manchus attacked Korea several times between 1627 and 1636. In addition to problems caused by attacks from without, great division was created by fights between factions of the yangban class. These factions, the Easterners and the Westerners, engaged in violent conflict that persisted from generation to generation. Beginning in the late seventeenth century, disgust at the conflict among the yangban elites led many scholars, officials, and common people to support the Silhak movement, which promoted the study of the physical sciences and technology in order to solve practical problems instead of focusing narrowly on the Confucian classics (silhak means “practical learning”). Silhak proponents also advocated numerous social reforms, including land reform and revision of Korea’s rigid social structure. These reformers argued that learning should promote the welfare of the people. They stressed social equality and the importance of Korean culture. Concern for the preservation of Korean culture was undoubtedly influenced by Korea’s relationship to the countries that surrounded it. Buddhism and Confucianism, the philosophy on which the Joseon dynasty was based, were both introduced by the Chinese. Korean writing, painting, architecture, and pottery were also influenced by China. For centuries, Korean scholars wrote with Chinese characters. Over the centuries, Korea had been invaded by Chinese, Khitans, Mongols, Japanese, and Manchus. Nevertheless, the constant influx of foreign ideas and material goods helped to reinforce in Koreans the separate sense of a distinctive Korean identity. Trying to differentiate themselves from Chinese, Mongols, and Japanese, Koreans like the Silhak reformers emphasized the importance of maintaining a Korean identity based on Korean history and culture.