Casimir IV Jagiellon

Lore & Background

Casimir was the third and youngest son of King Władysław II Jagiełło and his fourth wife, Sophia of Halshany. His mother was 40 to 50 years younger than his father, leading to speculation of adultery, but Sophia pledged an oath of innocence and the charges were dismissed. He was baptised on 21 December 1427 and named after his deceased brother. In his early years, Casimir was nursed by his mother and supervised by vice-chancellor Wincenty Kot and a knight named Piotr of Rytro. After the accession of his brother Władysław III to the throne of Poland, tutelage was assigned to Cardinal Zbigniew Oleśnicki, who neglected his duties due to reluctance towards Casimir.

Following the sudden death of Sigismund Kęstutaitis, Casimir was invited to Lithuania and proclaimed Grand Duke on 29 June 1440 by the Council of Lords, contrary to Polish wishes. The Polish side met this with hostility, even military threats. Casimir was underage, so supreme control was held by the Council, presided by Jonas Goštautas. He was taught the Lithuanian language and customs. During his rule, the rights of Lithuanian nobility were put on an equal footing with Polish szlachta, and he promised to protect the Grand Duchy's borders and not appoint persons from Poland to Lithuanian offices. He was the first ruler of Lithuania to be baptised at birth, becoming the first native Roman Catholic Grand Duke.

After the death of his brother Władysław III at the Battle of Varna in 1444, and a three-year interregnum, Casimir was elected King of Poland in 1447. He was crowned on 25 June 1447, becoming both King of Poland and Grand Duke of Lithuania. His reign was marked by efforts to harmonize the interests of Polish and Lithuanian nobility while maintaining his position as supreme ruler. The Tęczyński family mediated between the crown and the upper class, and in Lithuania, Grand Chancellor Mikołaj II Radziwiłł, nicknamed 'Amor Poloniae', strengthened ties with the Polish Crown while safeguarding Lithuanian autonomy.

Reader's Guide

Casimir IV Jagiellon's significance lies in his dual role as Grand Duke of Lithuania and King of Poland, a personal union that he maintained throughout his reign. His greatest triumph was bringing Prussia under Polish rule after defeating the Teutonic Knights in the Thirteen Years' War and recovering Pomerania. Under him, Poland became a significant power in international relations, with trade stimulated by demand for raw materials and semi-finished goods, contributing to the growth of crafts and mining. The Jagiellonian dynasty became one of the leading royal houses in Europe. His reign corresponded to the age of 'new monarchies' in western Europe. Casimir's legacy includes the equalization of rights for Lithuanian and Polish nobility, and his receipt of the English Order of the Garter. After his death in 1492, John I Albert succeeded him as King of Poland, and Alexander Jagiellon became Grand Duke of Lithuania.

Did You Know?

• Casimir was the first ruler of Lithuania to be baptised at birth, becoming the first native Roman Catholic Grand Duke.
• He was a recipient of the English Order of the Garter, the highest order of chivalry in England.
• His mother, Sophia of Halshany, was 40 to 50 years younger than his father, leading to accusations of adultery that were dismissed after her oath of innocence.
• The Prussian Confederation viewed his reign as a shift towards centralisation.