First built in 132 during the Baekje era (18 BC-AD 660) under King Gaeru's reign, Bukhansanseong Fortress was the northernmost fortress that protected Baekje from Goguryeo's forces. In the year 475, the fortress fell in the hands of Gogyuryeo after a fierce battle. As a result, King Gaeru was killed and Baekje's princess fled to Ungjinseong Fortress. Despite the fortress' collapse and reconstructions, Bukhansanseong Fortress continued to play an important role in protecting the capital city throughout Korea's history of war.