The Choson Dynasty was founded in 1392 by Korean general, Yi Song-gye. During this dynasty, the government turned to Confucian principals rather than Buddhism. One of this dynasty's greatest accomplishments was the creation of the written Korean language called, "hongul". As a result, Korea's literacy rate increased. Later in the 1590s, a Japanese ruler wanted to invade China through Korea. The Japanese ransacked and destroyed Korean villages, until Korean Admiral Yi Sun-shin used "turtle ships", or heavily armored ships, to defeat the Japanese fleet. Six years later, the Japanese fled carrying off Korean artisans to learn skills of Korea.