History of the Polish–Lithuanian Commonwealth (1569–1648)

History of the Polish–Lithuanian Commonwealth (1569–1648) covers a period in the history of Poland and Lithuania, before their joint state was subjected to devastating wars in the middle of the 17th century. The Union of Lublin of 1569 established the Polish–Lithuanian Commonwealth, a more closely unified federal state, replacing the previously existing personal union of the two countries. The Union was largely run by the Polish and increasingly Polonized Lithuanian and Ruthenian nobility, through the system of the central parliament and local assemblies, but from 1573 led by elected kings. The formal rule of the proportionally more numerous than in other European countries nobility constituted a sophisticated early democratic system, in contrast to the absolute monarchies prevalent at that time in the rest of Europe.

The Polish–Lithuanian Union had become an influential player in Europe and a vital cultural entity, spreading Western culture eastward. In the second half of the 16th and the first half of the 17th century, the Polish–Lithuanian Commonwealth was a huge state in central-eastern Europe, with an area approaching one million square kilometers.

Following the Reformation gains (the Warsaw Confederation of 1573 was the culmination of the unique in Europe religious toleration processes), the Catholic Church embarked on an ideological counter-offensive and Counter-Reformation claimed many converts from Protestant circles. Disagreements over and difficulties with the assimilation of the eastern Ruthenian populations of the Commonwealth had become clearly discernible. At an earlier stage (from the late 16th century), they manifested themselves in the religious Union of Brest, which split the Eastern Christians of the Commonwealth, and on the military front, in a series of Cossack uprisings.

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