Silla, another Korean kingdom in the southeast…
June 400 CE
Silla, another Korean kingdom in the southeast of the peninsula, requests the assistance of Goguryeo in 400 to defend against an alliance of a Japanese army, the Baekje kingdom to the west, and the Gaya Confederacy to the southwest.
In the same year, King Gwanggaeto responds with fifty thousand troops, defeats both Japanese and Gaya cavalry units, and makes both Silla and Gaya submit to his authority.