Casimir IV Jagiellon - Grand Duke of Lithuania

Grand Duke of Lithuania

The sudden death of Sigismund Kęstutaitis left the office of the Grand Duchy of Lithuania empty. The Voivode of Trakai, Jonas Goštautas, and other magnates of Lithuania, supported Casimir as a candidate to the throne. However many Polish noblemen hoped that the thirteen year old boy would become a Vice-regent for the Polish King in Lithuania. Casimir was invited by the Lithuanian magnates to Lithuania, and when he arrived in Vilnius in 1440, he was proclaimed as the Grand Duke of Lithuania on 29 June 1440 by the Council of Lords, contrary to the wishes of the Polish noble lords—an act supported and coordinated by Jonas Goštautas. This act could have been understood as dissolution of the personal union between the Grand Duchy of Lithuania and the Kingdom of Poland. When the news arrived in the Kingdom of Poland concerning the proclamation of Casimir as the Grand Duke of Lithuania, it was met with hostility, even to the point of military threats against Lithuania. Since the young Grand Duke was underage, the supreme control over the Grand Duchy of Lithuania was in the hands of the Council of Lords, presided by Jonas Goštautas. Casimir had been taught the language and customs of Lithuania by appointed court officials.

During Casimir's rule the rights of the Lithuanian nobility—dukes, magnates and boyars (lesser nobles), irrespective of their religion and ethnicity—were put on an equal footing to those of the Polish szlachta. Additionally, Casimir promised to protect the Grand Duchy's borders and not to appoint persons from the Polish Kingdom to the offices of the Grand Duchy. He accepted that decisions on matters concerning the Grand Duchy would not be made without the Council of Lords' consent. He also granted the subject region of Samogitia the right to elect its own elder. Casimir was the first ruler of Lithuania baptised at birth, becoming the first native Roman Catholic Grand Duke.