 By conquering Liaodong, Gwanggaeto recovered the ancient domain of Gojoseon; Goguryeo controlled Liaodong until the mid-late 7th century.In 589, the Northern and Southern dynasties period ended and the Sui dynasty unified China after four centuries of fragmentation.The Sui Empire reconquered Vietnam and defeated Champa, sacking its capital, and conquered important lands in northern China and Central Asia against Turks, Tibetans and proto-Mongolians.