The authorship of the letters between Abelard and Heloise has been the most controversial question in Abelardian scholarship for over a century. The opponents of the letters' authenticity divide into two main parties: those who believe that Abelard himself composed the whole correspondence, including the letters ostensibly by Heloise; and those who believe that, although they may use genuine material, the letters as they survive are a forgery, the work of neither of the authors who appear to have written them. The arguments against authenticity must be considered carefully, beginning with those put by advocates of the more radical position: that the correspondence (including the Historia) is a forgery.

The suggestion of forgery was first raised nearly two hundred years ago by Ignaz Fessler. Not until the 1970s, however, was it advocated in a coherent and detailed form, by the American historian, John Benton. Benton's was a complicated theory, which postulated at least two forgers – a ‘twelfth-century epistolary “novelist”’ and a ‘thirteenth-century institutional scoundrel’ – as well as a certain amount of authentic material; and it rested on a set of bold speculations about the practices and history of the Paraclete. Although greeted with alarmed respect by many Abelardian scholars, detailed investigation of Benton's arguments based on the liturgy and monastic institutions showed them to be without foundation It was also shown that Abelard's letters correspond with his other writings in a number of minute and characteristic ways which no forger would be likely to have imitated.