This dissertation is a study of medieval theological interpretations of fear and their influence on the rhetorical and didactic discourses of two late-fourteenth century Middle English homiletic poems, Cleanness and Patience. In Chapter 1 I analyze the various medieval conceptualizations of dread (morally valueless timor naturalis, morally culpable timor libidinosus, and morally laudable timor gratuitus) as discussed by scholars such as Peter Lombard, St. Thomas Aquinas and St. Bonaventure and in works such as biblical exegesis and theological encyclopaedias. In the second chapter, I examine ways in which these formal, learned Latin interpretations of fear were disseminated to a wider, vernacular Middle English audience. I do so by discussing how medieval preaching theory and practice and vernacular didactic and devotional treatises actively employed rhetorical and exhortative discourses of fear in an effort to encourage their audiences to forsake sin and pursue virtue. In Chapters 3 and 4 I show how Cleanness and Patience incorporate and employ the various theological conceptualizations of dread discussed in Chapter I and the rhetorical and didactic discourses of fear analyzed in chapter 2. I examine fear's presence within the larger narrative, thematic, rhetorical, and didactic structures of each poem, discussing the poet's precise use of scholastic interpretations of fear in his representations of characters, his vivid descriptions of death and destruction, and the ways in which he both implicitly and explicitly confronts his audiences with a variety of fearful discourses. I argue that the poet utilizes fear to promote a specific rhetorical strategy, one based upon a well-developed understanding of dread which should inspire in his audience the desire to flee from sin and damnation and approach fear-inspired, reverent perfection. Cleanness and Patience illustrate the power of God and the threat of sin, exhorting their readers to embrace and learn from the senses of dread they utilize and promote. Both poems provide remarkable examples of how particular elements oflearned Latin thought were adopted and developed by Middle English vernacular traditions.