King Taejo founded the Joseon Dynasty at Suchanggung Palace located in Gaeseong in 1392 but ordered the transfer of the capital to Hanyang (Seoul) within a month of his enthronement. As soon as Gyeongbokgung Palace, Jongmyo, and Sajikdan Altar were constructed (1395), the first king of Joseon began to build Hanyangdoseong according to the wall construction plan proposed by Jeong Dojeon.
In the plan, Hanyangdoseong was a long wall (about 18.2km) connecting Bukaksan (342 meters), Naksan (125 meters), and Namsan (262 meters) to Inwangsan (338 meters). The wall was supposed to be built as earthen ramparts on flatland and as a fortress on the hills. This vast and urgent project had to be done during the agricultural off-season. Most of the wall was completed by mobilizing 118,000 people from all over the country for 49 days in January and February 1396. During another 49 days of August and September, 79,400 were mobilized to complete the wall around Dongdaemun Gate, resulting in the completion of the Four Gates and the Four Lesser Gates of the new capital.
Twenty-seven years later, King Sejong launched large-scale expansion and renovation wherein the entire Hanyangdoseong would be rebuilt as stone fortresses. In 1422 (fourth year of King Sejong’s reign), the king mobilized around 320,000 workers and 2,200 technicians to complete the huge construction during the winter agricultural off-season. Since the population of Seoul at the time was about 100,000, the project was colossal; at least 872 people died during the construction. All of these have formed the backbone of Hanyangdoseong.
The wall had been repaired partially, with no significant collapse, for 260 years until the 30th year of King Sukjong’s reign (1704), when it was rearranged.