A photo of Ganghwasanseong Fortress taken at the time of the Japan-Korea Treaty of 1876

Ganghwado Island was the ideal refuge for the Joseon royal court as it was relatively close to Hanyang, and was blessed with natural defensive barriers, including the sea, which made it easy to defend. When Mongolian forces attacked the Goryeo Dynasty, the capital was moved to Ganghwa and continued to put up resistance, while during the Later Jin invasion of Korea in 1627 and the Machu Invasion of Korea in 1636, Ganghwa served as a refuge for the royal family.