In 1439, 21 years after King Sejong of the Joseon Dynasty came to power, the Mokpo garrison (jin) was established, which was designed to control twelve offshore islands. During the Japanese invasions of Korea (1592–1598), Admiral Yi Sun-sin established a garrison of naval forces at Mokpo and the island of Goha, to secure a base for provisions and ship repairs, such as the turtle ships, also known as the geobukseon and panokseon.