The Warsaw Confederation of 1573 was the culmination of religious toleration that was unique in Europe .
The Catholic Church soon embarked on an ideological counter-offensive , while the Union of Brest split the Eastern Christians within the Commonwealth .
The Warsaw Confederation of 1573 was the culmination of religious toleration that was unique in Europe , but the Catholic Church soon embarked on an ideological counter-offensive , while the Union of Brest split the Eastern Christians within the Commonwealth .