The rise of Christianity up to the victory of Constantine has often been studied and remains a puzzling phenomenon. In this valedictory lecture Jan N. Bremmer concentrates on the explanations adduced, focusing in particular on the works of three iconic figures from the last two hundred and fifty years: The History of the Decline and Fall of the Roman Empire of Edward Gibbon, the most famous ancient historian of all time, at the end of the eighteenth century; Die Mission und Ausbreitung des Christentums of Adolf von Harnack, the greatest historian of early Christianity of all time, around 1900, and The Rise of Christianity of Rodney Stark, the most adventurous sociologist of religion of our times, at the end of the twentieth century. Bremmer locates their concerns and explanations within their own times, but also takes them seriously as scholars, discussing their analyses and approaches. In this way he shows both the continuities and the innovations in the evolving view which scholarship presents of early Christianity. Bremmer's exceptional knowledge of the huge range of scholarship and his humane and balanced judgment make this lecture the ideal introduction to the many problems raised by Christianity's displacement of paganism.