Janusz Radziwill petitioned Pope Clement VIII for permission to marry Sophia on July 20, 1600. Because Sophia was adamant in her decision to remain Orthodox and raise any children in the Orthodox faith this led to a written discussion on the subject of interdenominational marriage between the Pope and the Patriarch of Constantinople. The ecumenical Union of Brest of 1596 realigning the Belarusian Church and the Ukrainian Church from the Patriarchate of Constantinople to the Holy See in Rome caused enormous grief for Sophia as she did not wish to convert to Catholicism, which was being practiced by most of the Polish and Lithuanian nobility (although apparently not by her husband-to-be Janusz, who was Calvinist).[1]