Pope Paul V, born Camillo Borghese, was head of the Catholic Church and ruler of the Papal States from 16 May 1605 to his death. In 1611, he honored Galileo Galilei as a member of the Papal Accademia dei Lincei and supported his discoveries. In 1616, Pope Paul V instructed Cardinal Bellarmine to inform Galileo that the Copernican theory could not be taught as fact, but Bellarmine's certificate allowed Galileo to continue his studies in search for evidence and use the geocentric model as a theoretical device. That same year Paul V assured Galileo that he was safe from persecution so long as he, the Pope, should live. Bellarmine's certificate was used by Galileo for his defense at the trial of 1633.