Union of Lublin

The Union of Lublin was signed on 1 July 1569 in Lublin, Poland, and created a single state, the Polish-Lithuanian Commonwealth, which was one of the largest countries in Europe at the time. It 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, a change prompted by the fact that Sigismund II Augustus, the last of the Jagiellons, remained childless after three marriages. The autonomy of Royal Prussia was largely abandoned, and the Duchy of Livonia, tied to Lithuania in real union since the Union of Grodno in 1566, became a Polish-Lithuanian condominium. The Commonwealth was ruled by a single elected monarch who acted as both King of Poland and Grand Duke of Lithuania, and it was governed with a common Senate and parliament, the Sejm. Some scholars see the Union as an evolutionary stage in the Polish-Lithuanian alliance, made necessary partly by Lithuania's dangerous position in its wars with Russia.