Andrei allied with the Livonian Order and Prince Svyatoslav II of Smolensk, who wanted to reconquer the Principality of Mstislavl.
[2] In February 1386, when Jogaila and his allies celebrated his wedding to Jadwiga of Poland and coronation as Polish king in Kraków, the Order invaded Lithuania, almost reaching Vilnius.
[2] Svyatoslav devastated many lands on the Lithuanian border and besieged Mstislavl, which was defended by Karigaila, son of Algirdas.
[4] The result of the battle was a complete defeat of the Smolensk troops and the deaths of Svyatoslav and his nephew Ivan.
Yuri, who according to the Bychowiec Chronicle was married to a niece of Skirgaila and Jogaila, was installed as the Prince of Smolensk and as a vassal to Lithuania.