Gwanggaeto the Great
Goguryeo's height of power came in the reign of Taewang Gwanggaeto the Great of Goguryeo, who created and strengthened Goguryeo's cavalry and naval units to pacify the south and the north. Gwanggaeto the Great attacked and conquered Buyeo, Biryu-guk, the Later Yan, Malgal, and the Ainu tribes. Goguryeo's height of power finally came, but the bringer of glory died at the young age of 39.