Sigismund III was a pious, Jesuit-educated Catholic who supported Counter-Reformation. Back in 1596, he has already forced a union with Catholics (Union of Brest) on Orthodox in the Commonwealth, with a rather underwhelming results.

As for religious tolerance, while by the early 17th century it was still remarkable by European standards of the day, the height of both Protestant influence and somewhat anti-Clerical sentiments among the Catholic nobility has already passed.

Within the first decades of the 1600s the Protestant and Orthodox political position waned as prominent noble families began to convert to Catholicism (or convert back, in case of the protestants) and a new generation of Counter-Reformation supporting Catholics has started to dominate.