On this Day, in 1569: the Union of Lublin established the Polish-Lithuanian Commonwealth

On July 1, 1569, the Kingdom of Poland and the Grand Duchy of Lithuania signed the Union of Lublin, establishing the Polish–Lithuanian Commonwealth, one of the largest and most populous countries of 16th century Europe.

The Kingdom of Poland and the Grand Duchy of Lithuania had been in a de facto personal union since 1386 and the marriage of the Polish queen Hedwig to Lithuania’s Grand Duke Jogaila, who was crowned King Władysław II Jagiełło of Poland.

Saving the “Eternal Union”

By the second half of the 16th century, Lithuania started facing the threat of incorporation into the Tsardom of Russia, and Sigismund II Augustus, King of Poland and Grand Duke of Lithuania, pressed for a real union.

Another clear motivation for Sigismund, who was the last male member of the Jagiellons, was an attempt to preserve the continuity of his dynasty’s work and save the “Eternal Union” between the two countries.

Though the Polish nobility wanted full incorporation of the Grand Duchy of Lithuania, the Lithuanians continued to oppose that, one point of contention being the right of Poles to settle and own land in the Grand Duchy.

But after months of negotiations and under pressure by Ruthenian nobles, who were eager to capitalise on the economic and political opportunities offered by the Polish sphere and wanted their lands to become a part of the Polish Crown, the last objections were overcome.

Union of Lublin

Signed in July 1569, the Union of Lublin formally established the Polish–Lithuanian Commonwealth, which replaced the personal union of the Crown of the Kingdom of Poland and the Grand Duchy of Lithuania with a real union and an elective monarchy.

Also known as the Commonwealth of Two Nations, the new state became ruled by a single elected monarch who carried out the duties of King of Poland and Grand Duke of Lithuania, and governed with a common Senate and Parliament.

The Commonwealth possessed many features unique among contemporary states, characterized by strict checks upon monarchical power, and is seen as a precursor to modern concepts of democracy, constitutional monarchy and federation.

One of the largest and most populous countries in 16th- to 17th-century Europe, the Commonwealth, at its largest territorial extent, covered almost 1,000,000 square kilometres and sustained a population of 11 million.

The rise and fall of the Polish-Lithuanian Commonwealth

The Union of Lublin was Sigismund’s greatest achievement and his greatest failure. Although the Union created one of the largest states in contemporary Europe, one that endured for over 200 years, Sigismund failed to push through the reforms that would have established a workable political system.

As a result, the royal power continued to wane, and the Commonwealth slid into a political anarchy that eventually cost it its very existence.

Throughout the 18th century, the Commonwealth started to be considered as a protectorate of the Russian Empire despite the fact that it was still an independent state. Attempts at reform, such as the May 3 Constitution, came too late, and the country was eventually partitioned in three stages by the Russian Empire, the Kingdom of Prussia, and the Habsburg Monarchy.

By the end of the 18th century, the Polish–Lithuanian Commonwealth had been completely erased from the map of Europe. Poland and Lithuania were not re-established as independent countries until 1918…

Find out more about Central European history in our new On this Day series.