Crooked Castle
Before becoming Grand Duke of Lithuania, Vytautas committed at least one disgraceful act that would bar any modern politician from achieving high office. In 1390 he led Teutonic knights in an attack on Vilnius and decimated the defenders of the Crooked Castle.
The raid on Vilnius at the end of summer 1390 was exceptional because alongside the Teutonic knights marched Lithuanian duke Vytautas and the future King Henry IV of England, who then was still known as the Earl of Derby Henry Bolingbroke (1367–1413). The assailants took and burned down the Crooked Castle where they killed Kazimierz-Karigaila, the brother of King Władysław II Jagiełło.
Learn more about how Vytautas and Teutonic knights attacked Vilnius by clicking on this link.