Because the Tale of Igor's Campaign is one of the very few sources that ties Dazhbog directly to a living sense of ancestry among the Rus, and because the poem survives only through an eighteenth-century copy that was destroyed in the Moscow fire of 1812 before independent scholars could examine the original medieval manuscript directly, the poem's authenticity has been the subject of a real and sometimes heated scholarly controversy rather than a settled matter.
A minority of respected scholars, including the French Slavist Andre Mazon in the mid twentieth century and later the American historian Edward Keenan, argued at length that the Tale was in fact an eighteenth-century literary forgery composed in a deliberately archaic style, pointing to peculiarities of language and to the suspicious circumstances of its discovery and subsequent destruction by fire.
The mainstream position among specialists in Old East Slavic philology, however, has held that the poem is a genuine twelfth century work, a view substantially reinforced by the large corpus of authentic medieval birchbark documents excavated at Novgorod beginning in 1951, which supplied independent, physically dated evidence of period vocabulary and idiom that specialists argue matches the Tale's own linguistic texture in ways a later forger working from limited eighteenth-century sources would have been unlikely to reproduce convincingly. The dispute matters directly for Dazhbog, since if the Tale were a later invention, its image of the Rus as the giving sun-god's grandchildren would be an eighteenth-century flourish rather than a trace of medieval belief, and readers should hold that possibility in mind even as most current specialists treat the poem, and its testimony about Dazhbog, as authentically medieval.