Any attempt to define the romance must necessarily undertake to determine the differentia that separate this species of narrative art from that to which it is most closely related, viz. the epic.
So far as formal or material tests are concerned, it is impossible to discover any infallible criterion by means of which the two species may be distinguished. In form both are metrical narratives and in subject-matter fictions dealing with heroic adventure and achievement. Such are the Iliad, the Beowulf, the Nibelungenlied, and the Chanson de Roland as representing the epic and the Fierebras, the metrical Morte d'Arthur, the Roman de Troie, and the Roman de Thèbes as representing the romance. Again, while both may under certain conditions vary from this norm, both will be found, when they do so vary, to pass through much the same range of variation. Both the epic and the romance may, particularly when embodied in works of an alien character, be short. Short, for example, is the epic recital of the Battle of Brunanburh embedded in the Anglo-Saxon Chronicle. Short likewise are those passages of romance sometimes incorporated in the epic or drama, as the story of the lotus-eaters in the Odyssey and the stories of “the three caskets” and of “the pound of flesh” in Shakespeare's Merchant of Venice. Similarly both the epic and the romance may, in the later stages of their development, be written in prose instead of verse. This is true of the Younger Edda as exemplifying the epic and the Huon de Bordeaux, the Merlin, and the Recueil des Histoires de Troie as exemplifying the romance. In prose is written likewise the large body of relatively late Greek romance from the Cyropedeia of Xenophon to the Heroicus of the Younger Philostratus.