This article deals with a famous but obscure issue in eleventh-century intellectual history: the debate between Lanfranc of Bec and Berengar of Tours about the interpretation of the Eucharistic doctrine. The main focus will be on the treatise which is taken to be Lanfranc's key contribution in the debate, De corpore et sanguine Domini (c. 1063). As for Berengar, I shall leave aside his main work, the reply to Lanfranc known as Rescriptum contra Lanfrannum, and from his earlier work I will be concerned only with what is needed to create the context for Lanfranc's contribution. The reason for the choice of material is not that I would consider Berengar's work as insignificant – quite the contrary. However, De corpore is a text of a very unusual kind and a proper treatment of it alone will suffice, I think, to put the whole Berengarian affair in a different perspective.

Traditionally, Lanfranc's contribution in De corpore has been treated highly appreciatively. This applies both to his views about the Eucharist and his standing in relation to methodological issues. In anglophone historiography, the appreciative evaluation has been sustained, above all, by a series of studies by Sir Richard Southern. In a seminal article of 1948, Southern exalted Lanfranc as an expert dialectician and wrote Berengar off as an unintelligent grammarian. The same kind of view is restated in Southern's two biographies of Anselm of Canterbury.