King T'aejo, Lee Song-gye abandoned Koryo Dynasty's capital, Kyesong, and
moved the capital to Hanyang, today's Seoul, and proclaimed it as the new
capital on Oct. 28, 1394.

The main construction work of Hanyang started with the project led by
Chung Do-jeon in Dec. 1394. The palace wall, Kungsong, were built from
the Kyongbok Palace, and took shape with the constructions at Chongmyo
Royal Shrine and Sajik. In 1396, 120,000 men from all across the country
were injected to build the city wall, Tosong, which was completed in 98days.

The length of the wall per district was 17km each and the construction
managers' names were carved on the walls they were in charge of. The
fortress wall ranges over four mountains in Seoul: Pukak-san (themountain behind today's president office, Chong Wa Dae), Inwang-san,Nak-san, and Nam-san. The capital's fortress wall was built for defence purposes.

The overall completion to build the city wall took about three decades but
the palace wall was built in a haste, in three months, so it had many
weak areas. Therefore, by King Sejong's era, the walls were rebuilt.
The fortress wall was first built in a mixture of earth and stone but it was rebuilt as a stone wall.

The Seoul fortress walls were meant to defend the capital and was built in
a three-layer structure. The central inner wall, Kungsong, surrounds the
Kyongbok Palace; the middle wall, To-song, surrounds the capital; and a
third exterior wall, Sansong, guards the city from outside
forces. Therefore, the Seoul fortress wall is a symbolic
wall representing the capital and protecting the palace, rather than being
a wall preparing battles against enemy attacks.

After suffering two major invasions from Japan (1592-1598) and from
Ching Dynasty (1636), the Choson Kings decide to build two
fortresses in Mt. Pukhan and Mt. Namhan, to prepare to fight against
enemies in emergencies.

Many points of the Seoul fortress wall was damaged by the Japanese between
the Japanese empire colonial period (1909-1945), under the name of urbandevelopment, and during the Korean War (1950-1953).

The wall that remain today were mostly restored in the 70's. Starting at
Tongdaemun, the East Gate of Seoul, the wall passes along west to
Nak-san, Songbuk-dong, Pukak-san, Inwang-san, Sekomjong, and ends at the
Pukhansan-song Fortress in Mt. Pukhan. The wall and the 4 large gates and
4 small gates were mostly rebuilt during the eras of King Sukjong,
Youngjo, Chungjo. The Seoul fortress wall is currently designated as
national historical site number 10.