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.