What empire did the a Korean kingdom defeat in 1231?
Siege of Kuju The Siege of Kuju which occurred in 1231 was a decisive Goryeo victory against the Mongol Empire. After the Mongol army crossed the Yalu river, it quickly captured almost all of Goryeo's border defenses. The Mongol army, however, ran into stiff resistance both at Anju and the city of Kuju (modern-day Kusong), commanded by General Park Seo.
Ara Gaya Ara Gaya, also known as Ana Gaya, Asiryangguk (아시량국, 阿尸良國)), and Alla (안라, 安羅), was a City-state kingdom in the part of Gaya confederacy, in modern-day Haman County of South Korea. As the confrontational foreign policy of Daegaya failed, Ara Gaya and its less confrontational policy gained support in the 540s AD.