沃爾斯克拉河
During Vytautas' reign, Lithuania reached the peak of its territorial expansion, but his ambitious plans to subjugate all of Ruthenia were thwarted by his disastrous defeat in 1399 at the Battle of the Vorskla River, inflicted by the Golden Horde. Vytautas survived by fleeing the battlefield with a small unit and realized the necessity of a permanent alliance with Poland.