the Siege of Szigetvár on 6September, Sokollu Mehmed Pasha ordered John Sigismund to return to Transylvania. In a letter written about this time to Cosimo I, Duke of Florence, the mercenary Giovanandrea Gromo described John Sigismund as "extremely benevolent, gracious, subtle in thought, wise, level-headed, industrious [and] brave". Gromo mentioned that John Sigismund spoke Latin, Italian, German, Polish, Hungarian and Romanian well, and could also speak Greek and Turkish. John Sigismund appointed a Calvinist bishop as the only religious leader of the Romanians in his realm in November 1566. The Diet also ordered that all Romanian priests who refused to convert to Calvinism were to be expelled, but this decision was not carried out. Influenced by Dávid and Biandrata, John Sigismund became receptive to Anti-Trinitarian ideas from early 1567. With John Sigismund's support, Dávid published five books to promote his views, reproving for idolatry those who accepted the dogma of the Trinity. John Sigismund and Hasan Pasha stormed into Upper Hungary in March 1567. However, John Sigismund was taken seriously ill in summer. The Transylvanian lords pledged to respect his last will when electing his successor. The Ottoman Sultan Selim II granted the Transylvanian lords the right to freely elect their monarch, only preserving the right to approve their decision. Before long, John Sigismund recovered. Freedom of religion The Diet met again in Torda in early 1568 and authorized preachers to "teach the Gospel" according to their own understanding. The Diet also declared that nobody should "suffer at the hands of others for religious reasons", stating that "faith is a gift of God". The Edict of Torda expanded the limits of religious freedom far beyond the standard of 16th-century Europe. The decree did not put a complete end to discrimination, because official status was granted only to the Catholic, Lutheran, and Calvinist clergymen, but Unitarian, Orthodox, Armenian, Jewish, and Muslim believers could also freely practise their religions. The Treaty of Adrianople, signed in February 1568, concluded the first war between the Ottoman Empire and the Habsburgs. According to the treaty, John Sigismund retained all territories that he had conquered from Maximilian II in the previous years. The envoy of the Ottoman Sultan Selim II in Paris suggested that John Sigismund should marry Margaret of Valois, but his proposal was ignored. Many theological discussions on the Trinity were organized in 1568, the first of them taking place in his presence in