A site in western Russia first mentioned in 863, when it was already a key stronghold controlling the portages between the Dnieper and the Western Dvina rivers and the route between the Moscow region and western Europe. The town also lay on the trade route between the Baltic Sea to the north and Kiev and the Byzantine Empire to the south. Excavations have begun to increase our knowledge of early medieval Russia. Stone and timber houses and five churches of the Pre-Mongol period have been discovered; colorful frescoes imitating Byzantine silks were found attached to the church walls.