Guthrunarkvitha I is immediately followed in the Codex Regius by a long poem which in the manuscript bears the heading "Sigurtharkvitha," but which is clearly referred to in the prose link between it and Guthrunarkvitha I as the "short" Lay of Sigurth. The discrepancy between this reference and the obvious length of the poem has led to many conjectures, but the explanation seems to be that the "long" Sigurth lay, of which the Brot is presumably a part, was materially longer even than this poem. The efforts to reduce the "short" Sigurth lay to dimensions which would justify the appellation in comparison with other poems in the collection, either by separating it into two poems or by the rejection of many stanzas as interpolations, have been utterly inconclusive.

Although there are probably several interpolated passages, and indications of omissions are not lacking, the poem as we now have it seems to be a distinct and coherent unit. From the narrative point of view it leaves a good deal to be desired, for the reason that the poet's object was by no means to tell a story, with which his hearers were quite familiar, but to use the narrative simply as the background for vivid and powerful characterization. The lyric element, as Mogk points out, overshadows the epic throughout, and the fact that there are frequent confusions of narrative tradition does not trouble the poet at all.

The material on which the poem was based seems to have existed in both prose and verse form; the poet was almost certainly familiar with some of the other poems in the Eddic collection, with poems which have since been lost, and with the narrative prose traditions which never fully assumed verse form. The fact that he seems to have known and used the Oddrunargratr, which can hardly have been composed before 1050, and that in any case he introduces the figure of Oddrun, a relatively late addition to the story, dates the poem as late as the end of the eleventh century, or even the first half of the twelfth. There has been much discussion as to where it was composed, the debate centering chiefly on the reference to glaciers (stanza 8). There is something to be said in favor of Greenland as the original home of the poem (cf. introductory note to Atlakvitha), but the arguments for Iceland are even stronger; Norway in this case is practically out of the question.

The narrative features of the poem are based on the German rather than the Norse elements of the story (cf. introductory note to Gripisspo), but the poet has taken whatever material he wanted without much discrimination as to its source. By the year 1100 the story of Sigurth, with its allied legends, existed through out the North in many and varied forms, and the poem shows traces of variants of the main story which do not appear elsewhere.