Thus Gibbon opened the thirty-seventh chapter of the History of the decline and fall of the Roman Empire, a lengthy chapter devoted to the twin topics of ‘the institution of monastic life’ and ‘the conversion of the northern barbarians’. The connection between the history of the Roman Empire and the Christian Church was indeed indissoluble. The Church was destined to follow the pattern of the empire by gradually degenerating as it grew in strength from original purity in the life of Christ and the Apostles to become a corrupt and baleful influence on the fortunes of secular society. Looking back over twenty years of research and writing (1767–87) he wrote near the beginning of his final chapter, ‘In the preceding volumes of this History, I have described the triumph of barbarism and religion and I can only resume in a few words, their real or imaginary connection with the ruin of ancient Rome.’ He goes on to list ‘potent and forcible causes of destruction’ by barbarians and Christians respectively. As he finally laid down his pen on 27 June 1787 at Lausanne, he concluded with a sentence whose strict accuracy has sometimes been doubted: ‘It was among the ruins of the Capitol that I first conceived the idea of a work which has amused and exercised twenty years of my life, and which, however inadequate to my wishes, I finally deliver to the curiosity and candour of the public.’ The date of this decision was 15 October 1764. Here we survey briefly the role of ‘religion’, i.e. Christianity in the ruin of the Roman Empire.

Marcel Bataillon is a notable instance of a scholar who found his line early and pursued it unremittingly. His Érasme et I'Espagne was published in 1937; a translation into Spanish appeared in 1950, with a second edition in 1966; but the original work has long been out of print and commonly unavailable. Thanks to Bataillon for ‘most important help’ were expressed in volume vii of P. S. Allen's Opus epistolarum Erasmi Roterodami, published in 1928, and again by Allen's widow in volume xi, published in 1947.