Balhae became a powerful empire like its predecessor, but its eventual end came at the hands of the Khitan Empire in 926. Balhae's end was a decisive event in Northeast Asian history for it was the last Korean kingdom to hold territory in Manchuria. Goguryeo was revived once more in 918 by successor state Goryeo, founded by Wang Geon, a descendant of Goguryeo nobility. In 937, much of the ruling class and the last crown prince of collapsed Balhae fled to Goryeo, where he was warmly welcomed and included into the ruling family by Wang Geon, thus unifying the two successor nations of Goguryeo.