In this chapter I explore some of the ways in which Christians living in the region that we think of today as western Europe during the medieval period came to perceive Islam, the new faith that emerged in the Arabian peninsula in the third decade of the seventh century and rapidly spread across much of the world as it was then known to them. As we will see, even the initial western Christian perceptions of Islam and of its adherents did not come out of nowhere or develop in a vacuum. Seventh-century “Europeans” – of course they did not think of themselves as Europeans at the time – already possessed concepts and categories through which this new and frightening phenomenon could be made sense of. Some of these concepts and categories, and the images they generated, would prove quite durable over much of the medieval period, though by the end of this period a handful of scholars had begun to lay the basis for a somewhat better understanding of Islam.

To adequately understand the development of western Christian images of Islam, it is helpful to go even further back in time, to ancient Greece and Rome, and there begin to explore the origins and evolution of the idea of a “Europe” and a “West” often deemed essentially different from an “East.” Over the succeeding centuries these and other ideas and images would be drawn on, in different ways and in changing contexts, to underpin certain ways of dividing the world and categorizing its parts, and thus of understanding Islam.