Fall of Hanseong and Move to Ungjin
King Jangsu took the Baekje capital Hanseong with 30,000 troops and killed King Gaero; Baekje moved its capital to Ungjin (Gongju).

Sadopaul · CC BY-SA 4.0 · Source
Jangsu is said to have sent the monk Dorim to lure Gaero into ruinous building projects before attacking. Hanseong fell in seven days and Gaero was captured and executed. Munju, who had gone to seek help from Silla, returned, took the throne and moved the capital to Ungjin.
Goguryeo now held the Han River basin and pushed south to a line from Asan Bay to Jungnyeong Pass, as the Chungju Goguryeo Stele shows.