A war had broken out in 1386 between Algirdas' sons, Skirgaila and Andrei of Polotsk.

The latter had fled from Polotsk to Smolensk and asked its prince for help.

The armies of Smolensk and Skirgaila clashed near Mstislavl in the Battle of the Vikhra River.

After the prince was killed in battle and his brothers were taken prisoner, the Lithuanians approached Smolensk and allowed his son Yury to assume the throne on certain conditions, after exacting a sizable indemnity from him.

While Yury was visiting his father-in-law, Oleg Korotopol of Ryazan, in 1395, Grand Duke Vytautas the Great (Vitovt) of Lithuania had taken Smolensk and installed his governor there.

Four years later, Vytautas had been routed by the Tatars in the Battle of the Vorskla River.

In 1401, Yury and Oleg make use of his plight to retake Smolensk and …