This thesis is a comparative study of the Medieval influence on the creation of John Milton’s Paradise Lost, and the purpose of this thesis is to establish Paradise Lost as a poem designed to correct what Milton saw as the errors of the Medieval theological worldview. A range of topics are discussed, from the loyal angels to the Garden of Eden to Hell and Satan, and particular attention is given to Dantean parallels in these areas of Milton’s poem. The thesis shows how Milton responded to such Medieval concepts as courtly love and salvation theory and demonstrates how Milton elaborates on, corrects, or repudiates Medieval literary and theological notions. In doing so, Milton has not only created the great English epic that he envisioned; he has produced a truly Protestant epic. Much attention has been given to the Miltonic influence on the Romantic period and to the influence of the classical poets on Milton. The contrasts and parallels between Milton and his Medieval predecessors has garnered much less attention but is equally important to a complete understanding of Milton as a man and poet. An appreciation of the Medieval influence on the poem Paradise Lost allows the reader to gain a fuller understanding of Milton’s own theological beliefs, and it will also help the reader to see how Paradise Lost took the form that it did.