The Jagiellonian Dynasty and the Radziwiłł Family

The union between the Crown of the Kingdom of Poland and the Grand Duchy of Lithuania began with the Union of Krewo in 1385, which laid out the prenuptial commitments of the Grand Duke of Lithuania, Władysław Jagiełło, to the Kingdom of Poland. The Polish-Lithuanian union was renewed and strengthened multiple times through the shared person of the monarch, until a formal act—the Union of Lublin in 1569—established a single state known as the Polish–Lithuanian Commonwealth, which lasted until 1795.

The Jagiellonians

The founder of the dynasty that ruled Poland for nearly 200 years was Władysław Jagiełło. Through strategic dynastic policies, the Jagiellonians came to reign over the Kingdom of Poland, the Grand Duchy of Lithuania, the Kingdom of Bohemia, and the Kingdom of Hungary. Situated in the heart of Europe, the country underwent numerous territorial changes throughout its history, but it was during the Jagiellonian era that the Polish-Lithuanian state became the second largest country in Europe by land area.

The last ruler of the Jagiellonian dynasty was Sigismund II Augustus, the son of Sigismund I the Old and Bona Sforza, who was crowned during his father's lifetime in 1530. As the hereditary ruler of Lithuania, he governed there independently for several years. In 1548, following the death of Sigismund the Old, he ascended the Polish throne. His greatest achievement was the conclusion of the Polish-Lithuanian Union in Lublin in 1569. Under this union, a common monarch, parliament (Sejm), currency, and foreign policy became the foundations of state unity, while separate treasuries, offices, armies, and judicial systems were preserved. Although Sigismund Augustus was married three times—first to Elizabeth of Habsburg, then to Barbara Radziwiłł, and finally to Catherine, Elizabeth’s sister—he had no male heir to ensure the continuity of the dynasty. Despite conflicts on the fringes of the state, his reign is remembered as a time of peace and economic growth. While religious wars raged across Europe, the Jagiellonian Commonwealth stood out as a true mosaic of nations and faiths. This atmosphere fostered cultural development shaped by Renaissance humanism and the Reformation, allowing Polish science and the arts to reach a European level of excellence.

The Radziwiłł Family

The first, historically sourced, ancestor of the Radziwiłł family, according to records, was Ościk (d. ca. 1444), a member of the Lithuanian Council of Lords and castellan of Vilnius. During the Union of Horodło in 1413, he received the Trąby coat of arms from Bishop Mikołaj Trąba. Among his four sons, the most notable figure was Radziwiłł (d. ca. 1477), whose name would later become the surname of the family, beginning with the third generation. His only son, Mikołaj Radziwiłłowicz (ca. 1440–1509), who served as voivode of Vilnius and Lithuanian chancellor, led the Council of Lords of the Grand Duchy of Lithuania and continued his father’s policies, significantly enhancing the family's influence. He played a crucial role in the appointments to the Lithuanian grand ducal throne—first securing it for Alexander Jagiellon, and later for his brother, Sigismund. Mikołaj’s daughter, Anna, married Duke Konrad II of Masovia, while his three sons founded three branches of the family, named after their respective estates: Goniądz and Medely (Myadzyel) (founded by Mikołaj Radziwiłł), Biržai and Dubingiai (by Jerzy Radziwiłł), and Nieśwież, Kletsk, and Ołyka (by Jan Radziwiłł). Jerzy’s daughter was Barbara Radziwiłł, who later became Queen of Poland.

Fascinating facts

In the Central Archives of Historical Records in Warsaw, the Act of the Union of Lublin intended for the Polish estates is still preserved. A second original copy, along with Act of the Union of Horodło, was kept from the mid-17th century in the castle at Nieśwież. In 1919, these documents were transported to Warsaw for safekeeping. During World War II, they were stored in the palace of Janusz Radziwiłł on Bielańska Street. Both acts were lost during the Warsaw Uprising.

During the reign of Sigismund Augustus, the Nieborów estate was already highly fragmented and held by several members of the Nieborowski family, who bore the Prawda coat of arms. On the site of today's palace stood a Gothic-Renaissance manor house with farm buildings. These lands bordered the estates of the Archbishops of Gniezno, whose main seat was nearby Łowicz. During the reign of Sigismund I the Old, the Archbishop of Gniezno and Primate of Poland was Mikołaj Dzierzgowski (c. 1490–1559), who crowned both Barbara Radziwiłł and the king’s last wife, Catherine of Habsburg. He was succeeded by Jakub Uchański (1502–1581), who, after the death of the last Jagiellon, became the first interrex in history—a high-ranking state official who temporarily held royal authority during an interregnum. During such periods, Łowicz became the de facto second capital of Poland. Both primates were active in improving the town and transformed the local castle (now in ruins) from a Gothic structure into a Renaissance residence that hosted prominent guests, including kings, papal nuncios, and foreign envoys.

Architectural fragments from primatial castle, now decorate the walls of the High Priest's Shrine in Arkadia. These elements were acquired by Helena Radziwiłł in the late 18th century.

In the 16th century, the nearby town of Bolimów was counted among the 100 largest cities of the Polish–Lithuanian Commonwealth. It occasionally hosted provincial noble assemblies (sejmiki), where delegates were chosen for national parliaments (sejm) and for the Tribunal in Radom, which controlled taxation. On November 18, 1556, while traveling from Łomża to Piotrków for a parliamentary session, Sigismund Augustus stopped in Bolimów and reaffirmed the privileges previously granted to the town. On January 30, 1574, the funeral procession carrying the remains of the last Jagiellon passed through Bolimów.

Bust of Barbara Radziwiłł

Artist: Unknown

Date: 19th century (?)

Collection: The collection of Maciej Radziwiłł