 Although empiricism is often thought to be a modern doctrine, it has ancient roots, and its modern forms are built on late medieval developments. This article will begin by outlining three different forms of empiricism. It will examine the Presocratic and Hippocratic origins of the empiricist attitude, and discuss its development in the work of Aristotle, the Hellenistic medical writers, sceptics, and Epicureans. It will then examine the combination of Aristotelian and Augustinian views in the work of thirteenth and fourteenth-century thinkers, the connection between the study of magic and empiricism, the eclipse of the doctrine of divine illumination, and the gradual downplaying of the role of the intellect in the acquisition of knowledge.