Quoted By:
probably the battle of the Vorskla River
after his predecessor duke Algirdas defeated the Golden Horde in the battle of the blue waters Vytautas continued the eastern expansion.
He gathered a large army of 38k men from Lithuania and his rus vassals as well as his allies Moldavia, Wallachia and Teutonic knights.
the expansion was successful and even reached Crimea but they were defeated at Vorska River by 90k strong Golden Horde army. The entire army was massacred and only Vytautas and few other dukes managed to escape
