 No distinct trace of anti-Trinitarian opinion precedes the appearance of Giorgio Biandrata at the Transylvanian court in 1563.His influence was exerted on Ferenc Dávid (1510–1579), who was successively Roman Catholic, Lutheran, Calvinist and finally anti-Trinitarian.Some argue that the growth of anti-Trinitarian opinion in Transylvania and Hungary may have partly been due to the growing Islamic influence of the expanding Ottoman Empire at the time.