The entry of Silla into the Chungju Area is estimated to be around A.D. 551 when Silla occupied the basin of the Han river. The traditional structure of Silla's stone fortress, which the Chungjusanseong Fortress displays, has a weaker wall structure compared to the Samnyeonsanseong Fortress built around the late 5th century. This kind of structure is evident until around the middle and late 6th and the early 7th centuries.
Gukwon Subcapital was installed in 557 in the modern Chungju Area. The Gukwonseong Fortress -with 2,592 bo(步) in circumference, was built in 673- is speculated to be the current Daerimsanseong Fortress. The fortress construction technique of Silla in the mid to late 7th century under the reign of King Munmu shows a recognition of the merits of the construction techniques of Baekje and Goguryeo. The construction of fortresses formed a part of the reorganization of the defense system in order to secure the safety and sovereignty over the major provinces in this period.
Gukwon Subcapital was renamed to Jungwon Capital in 757. Yonggwandongsanseong Fortress and Jangtaesanseong Fortress are located at a transportation hub and functioned as the defense system with other fortresses formerly built including the Jangmisanseong, Chungjusanseong, and Daerimsanseong Fortresses.
That the Jungwonbu, Gukwon, Chungju replaced the name of Jungwon Capital after the late 9th century demonstrates the chaotic situation of the Later Three Kingdom Period which was dominated by powerful local clans. The Kyeonhakri Earthen Fortress and the multiple moat site in Jangtaesanseong Fortress, constructed on the hills surrounded by the plains and transportation hub, display new patterns.