The life of Philipp Jaffé (1819-1870), from his youth in Posen; his studies with Leopold von Ranke and career - as a close friend of Theodor Mommsen - at the pinnacle of historical scholarship in Berlin, first at the Monumenta Germaniae Historica and then, after his feud with Georg Heinrich Pertz, with his unprecedented 1862 appointment, while still a Jew, to a Berlin professorship; and on to his baptism in 1868 and suicide in 1870, was a life of transition between East and West and between Judaism and Christianity - and a life of devotion to scholarship, of loneliness, of success and of frustration. Forgotten today, except by medievalists who depend on his numerous editions of Latin texts, Jaffé was a central figure in the heydays of German scholarship. His career illustrates the working conditions of such scholars, their friendships and feuds, and also the limits that hemmed Jews in and the ways they could be overcome. This volume documents Jaffé's life, accomplishments, and struggles, and also offers insight into his soul via more than two hundred of his letters (in German) - about half to his parents in Posen and half to colleagues around Europe, especially Pertz and Mommsen.