Korean Peninsula

North–South States Period

Beginning in the 6th century, Silla's power gradually extended across the Korean Peninsula. Silla first annexed the adjacent Gaya confederacy in 562. By the 640s, Silla formed an alliance with the Tang dynasty of China to conquer Baekje and later Goguryeo. After conquering Baekje and Goguryeo, Silla repulsed Tang China from the Korean peninsula in 676. Even though Silla unified most of the Korean Peninsula, most of the Goguryeo territories to the north of the Korean Peninsula were ruled by Balhae. Former Goguryeo general or chief of Sumo Mohe Dae Jo-yeong led a group of Goguryeo and Mohe refugees to the Jilin and founded the kingdom of Balhae, 30 years after the collapse of Goguryeo, as the successor to Goguryeo. At its height, Balhae's territories extended from southern Manchuria down to the northern Korean peninsula. Balhae was called the "Prosperous Country in the East".