Jómsvíkinga saga is difficult to classify generically. Modern conceptions of history and fiction in any case rely on different assumptions from those of medieval authors. Recent attempts to relocate another anomalous text, Yngvars saga víðfǫrla, within the fornaldarsögur has implications for Jómsvíkinga saga. The saga has an intricate two-way relationship with the konungasögur, and is set against a background of historical events, but its narrative is ahistorical, particularly in its personalization of events. The saga shows a development over time, with later versions including more fantastic elements; the inclusion of verse, on the model of the konungasögur, was also a later development. The saga shows a particular interest in the dynamics of relationships within a warrior group, rather than singling out an individual hero. There is a polarity between the heroic Vagn and the treacherous Sigvaldi, whose defection brings about the downfall of the group. Despite sharing material with the konungasögur, the saga’s preoccupations are distinctive and defy genre classification