The variety of scholarly approaches to the Middle High German poem Das Nibelungenlied has generated a wide range of conflicting analyses of the character of Hagen, a figure who plays a key role in both the plot and the interpretation of the work. This thesis proposes that viewing Hagen’s relationship with Siegfried in relation to the poem’s central theme of loyalty (triuwe) allows for an analysis that integrates both the positive and negative aspects of Hagen’s character. By examining the depiction of courtly rivalry in four contemporary Middle High German works (Herzog Ernst B, Wolfdietrich A, Tristan, and Parzival), I outline the basic features of this common medieval narrative structure and then apply the same framework to a close reading of the relationship between Hagen and Siegfried in the Nibelungenlied. I also argue that the incorporation of the courtly rivalry motif as a unifying theme of the text allows the poet to take a stance on the broader issue of loyalty conflict, a topic which appears frequently in contemporary literature and had particular relevance within the political climate of medieval Germany. My reading of the character of Hagen can thus hopefully shed new light on the thematic structure of the Nibelungenlied as well as on the relationship between the poem and the literary and historical context in which it was written.