Vorskła, Battle of (1399), one of the major battles connected with the eastward expansion of the Grand Duchy of Lithuania (GDL) under Grand Duke Vitaŭt. The battle took place in Ukraine on the banks of the Vorskła River, the Dnieper's left tributary. Vitaŭt had between 15,000 and 20,000 soldiers, among whom were several thousand Tatar allies of Khan Takhtamysh, his ally, who was challenging the ruler of the Golden Horde, Khan Timur-Kutluk. Also, there were Polish, German, and Wallachian units, since Vitaŭt's move was blessed by the pope as a crusade. However, Vitaŭt's army suffered a debacle at the hand of the superior army of Timur-Kutluk. Many thousands of Vitaŭt's host perished. He and Takhtamysh managed to escape. The defeat doomed Vitaŭt's ambition to unite the lands of Ruś under his helm.