Offa’s Dyke: a historiographical appraisal

Offa’s Dyke is one of the largest and best known, if rather less well understood, field monuments in Britain. Despite this, there have been very few primary studies of it. This article makes a critical examination of the principal bodies of work dealing with the dyke. It argues that in many respects our knowledge is less certain than is usually believed. In particular it discusses the time and labour necessary for the construction of the earthwork and it is suggested that it could have been constructed much more quickly, and with a much smaller workforce, than is generally supposed. More fundamentally, the purpose and function of Offa’s Dyke are considered, and it is argued that, in addition to any practical utility it may have had, the earthwork had important ideological significances that until recently have been largely neglected. Specifically, it is argued that the dyke was a manifestation of eighth-century Mercian royal ideology, intended to consolidate the power of the Mercian kingship, in the west midlands in particular and southern England more generally.