For a number of years now, ‘imagined geographies’ have been a focus of much discussion among ‘post-colonial’ geographers, sociologists and anthropologists. However, most of this work has been concerned with European overseas colonialism and the cultural construction of the colonised ‘Other’ in eighteenth-, nineteenth-and twentieth-century contexts, and largely overlooks the possibility that such ‘Othering’ of subject populations has a long history within Europe (see Driver and Gilbert 1999; Godlewska and Smith 1994; Gregory 1995; Lester 1998). The purpose of this chapter is to examine such processes by exploring how, in the eleventh and twelfth centuries, an ‘Anglo-centric’ feudal aristocracy viewed the western parts of Britain and Ireland as peripheral (and thus marginal and inferior) compared with southern and eastern areas of England, and how they put this medieval imagined geography of the ‘Celtic fringe’ to use in order to legitimise their territorial claims in Wales and Ireland.