Gregorovius (1821 - 1891) was born in Neidenburg, East Prussia, in a family of jurists and theologians. He studied theology and philosophy at the University of Königsberg. In 1852 he moved to Italy and resided in the country for over 20 years. In 1875 he joined the Bavarian Academy of Sciences, and in 1876 was named honorary Roman citizen and member of the Accademia dei Lincei.
His best known works are Wanderjahre in Italien, an account of his travels led through Italy in the 1850s, and the monumental Die Geschichte der Stadt Rom im Mittelalter (History of Rome in the Middle Ages), a classic studies of medieval and Renaissance history. He also wrote biographies of Pope Alexander VI and Lucrezia Borgia, and work on Byzantine history and medieval Athens. His works have been widely translated into English, French and Italian.