In 14th-15th century the upper course of the Yug, around Nikolsk, was a disputed territory between Grand Duchy of Moscow and Novgorod Republic. Novgorod controlled the major part of Russian North, and, in particular, all areas along the Sukhona, whereas Moscow controlled Veliky Ustyug, which it inherited from the Vladimir-Suzdal Principality. The Yug was the waterway Moscow used to get to Veliky Ustyug.