In the 1540s he studied in Rome along with his brother Cornelis II Floris (Floris, Cornelis II), who became a successful sculptor, engraver, and medalist. Returning to Flanders, Frans quickly took charge of a workshop in Antwerp. He became a phenomenal success thanks to his fashionable Mannerist (Mannerism) style, his technical facility, and his ability to organize an efficient picture-producing factory. He painted religious works and Classical allegories in a rather artificial style that borrowed heavily from Michelangelo and the Italian Mannerists in its elegant rhetoric and cool eroticism. Floris trained Marten de Vos, Lucas de Heere, Frans Pourbus the Elder, and many other young painters in his studio, and the Mannerist style that he and his brother evolved remained dominant in Flanders until the end of the 16th century. Floris's lifestyle and expenditures were extravagant, however, and he died overwhelmed with debts.