Interesting article ;) Can't read all of it though, cause i have to go. Maybe later.
The Warsaw Confederation (January 28, 1573), an important development in the history of Poland and Lithuania, is considered the formal beginning of religious freedom in the Polish-Lithuanian Commonwealth. While it did not prevent all conflict based on religion, it did make the Commonwealth a much safer and more tolerant place than most of contemporaneous Europe, especially during the subsequent Thirty Years' War.
This act is remarkable in that it was not imposed by a government or by consequences of war, but rather resulted from the good will of members of Polish-Lithuanian society. It was also influenced by the 1572 French St. Bartholomew's Day Massacre, which prompted the Polish-Lithuanian nobility to see that no monarch would ever be able to carry out such an act in Poland.
This country became what Cardinal Stanislaus Hosius called “a place of shelter for heretics”. It was a place where the most radical religious sects, trying to escape persecution in other countries of the Christian world, sought refuge. All religious sects in Poland enjoyed tolerance as such was the King’s will.
“Certainly, the wording and substance of the declaration of the Confederation of Warsaw of 28th January 1573 were extraordinary with regards to prevailing conditions elsewhere in Europe; and they governed the principles of religious life in the Republic for over two hundred years.” - Norman Davies