St. Michael the archangel appears by name in scripture only five times: three times in the Old Testament (Daniel 10:13, 21 and 12:1) and twice in the New Testament (Revelation 12:7-9 and the Epistle of Jude 9). Despite this relative paucity of references to the archangel in canonical literature, there exists a vast store of legendary material from the Middle Ages concerning the archangel's roles in the unfolding of human history. In this chapter, I explore the literary origins of St. Michael's medieval legendary roles by examining the representations of the archangel in biblical and extra-biblical literature. The development of the archangel's roles in this literature as healer and guardian, intercessor, psychopomp, and warrior-angel accounts for his popular appeal in early medieval England. Indeed, the representations of the archangel in the literature reviewed in this chapter can be seen as having served as the principal quarry for early medieval English writers in their representations of St. Michael the archangel.