Pope Benedict XVI has written 66 books, three encyclicals, and three apostolic exhortations. The following is a list of Papal encyclicals written by Pope Benedict XVI. Reported messages from Jesus have also influenced papal actions and encyclicals. Thus Leo XIII, the Rosary Pope issued eleven Marian encyclicals. A number of papal encyclicals have been written by ghostwriters. Thus Leo XIII, the Rosary Pope, issued eleven Marian encyclicals. Since the 19th century, popes began to use encyclicals more frequently. Since the 19th century, Popes begin to use encyclicals more frequently. The magisterium of Pius XII is therefore significantly larger than the below listed 41 encyclicals. Under Pope Leo XIII Zigliara contributed to the encyclicals "Aeterni Patris" and "Rerum novarum". Leo XIII promulgated Marian devotions via eleven encyclicals on the rosary. During his seven-year pontificate, Benedict XV wrote a total of twelve encyclicals. It is considered third in importance, after apostolic constitutions and encyclicals. This is a list of encyclicals of Pope Pius XII. John Paul II addressed the issue in several encyclicals and public appearances.