The prose poem “Dar-thula” was first published as one of the companion pieces to the epic poem Fingal (1762). Among the longer items in the volume, it combines features of the extended epic with those of the shorter lyrical and dramatic fragments. The poem, which opens with Ossian's famous address to the moon (“Daughter of heaven, fair art thou”), relates the love and death of Darthula, daughter of the chieftain Colla. She falls in love with the youth, Nathos, but dies with him and his two brothers in armed struggle with Cairbar, usurper of the throne of Ireland, who was also in love with her. A remarkable feature of the original poem is its interplay of present, past, and future as Ossian, serving as narrator, comments on the fate of Darthula and her beloved Nathos.

Macpherson, who keeps close to traditional Gaelic accounts, commented in his notes that the heroine's name means “a woman with fine eyes” and that Darthula “was the most famous beauty of antiquity.” Her counterpart in Irish tradition is Deirdre, who remains alive to lament the death of her brothers, while Darthula, after witnessing her brothers’ fate, dies when an arrow pierces her side, and she falls on the body of Nathos. Even when this original narrative was modified (as in Herder's versification of the final scene) or drastically altered for local conventions (as on the Italian stage), the story of the beautiful Darthula drew a response from composers who recognized its universal appeal. Those who set “Dar-thula” over a span of two centuries inevitably faced the problem of having to negotiate between personal understanding of the poem's content and prevailing compositional standards.

In terms of period, the musical settings of “Dar-thula” fall into three main groups. The first, a “pre-Romantic” or early Romantic cluster, runs from a manuscript song by Karl Siegmund von Seckendorff (1774) to Stefano Pavesi's opera Ardano e Dartula (1825). Second is a full-fledged Romantic group stretching from Otto Ernst Lindner's Lied (1855) to a fragment by the German-American composer Hermann Hans Wetzler (1888).