In spite of the popularity which the poem here edited for the first time seems once to have enjoyed,The sixth stanza of the poem is quoted as an example of the metre called from its swinging rhythm, lúasc, see-saw, or láid lúascach, in the metrical treatise edited by Thurneysen, iii, pp. 55 and 87; and the same stanza is cited in a glossary in H. 3. 18, p. 423, to illustrate the use of the word bras .i. móor. it has reached us, so far as I am aware, in a single copy only. This is to be found in fo. 9b 2–10a 1 of the well-known Bodleian Codex Laud 610, a manuscript written in the fifteenth century. It is there ascribed to the celebrated Ulster poet Ruman mac Colmáin, whom the Book of Leinster calls the Homer and Vergil of Ireland.Ruman mac Colmáin in fili, diatá Síl Rumain i nAth Truim. Tri filid in domain .i. Homer ó Grécaib &ersir; Fergil ó Latinnaib &ersir; Ruman ó Gaedelaib. — LL. 354b (). But this attribution is erroneous. For, according to the Annals, Ruman died in A. D. 747,Ruman mac Colmain, poeta optimus, quievit. — ( 17, p. 249). while on linguistic evidence no higher age can be claimed for our poem than the eleventh century. The Old Irish neuter muir, sea, is in the third stanza used as a feminine (gusan glasmuir ngarglethain), assonating with anair and torcabair), a use of which I have no instance earlier than that century. Other phenomena that point to the same or a later period are: the use of the preposition dar with the dative dar a hardimlib, 1), the occurrence of the third person singular of the present indicative in -enn and -ann fris' funenn grían 3. co mbenann 6), the form torcabair (3) instead of torcabar, and the use of rócht as a monosyllable (9) instead of roächt, which is the form in the (e.g. line 6446), while Flann Manistrech, like our poet, has dorócht (LL. 181a 44). The mention in the fifth stanza of the craini gréineThis tree is mentioned by the same name in the Irish version of Marco Polo (see Stokes' edition, , 1, p. 250, paragraph 11 ^{online at CELT in file G305002.}. In a poem on St. Brendan the Navigator in LL. 366 m. inf., the island of Taprofane (Ceylon) is said to rest on it as on a pillar: i ti'r thall Taprofane, dianid áge crand gréne. As to the notion of islands being supported on one or more pedestals, see the , p. 47. or Tree of the Sun, i.e. the chenar or Oriental plane, shows that the author was acquainted with the legend of Alexander, which was not introduced into Ireland before the tenth century.

The manuscript copy of our poem is followed by a late (fourteenth century?) prose account of the circumstances under which Ruman is said to have composed it. This prose has twice been edited and translated, by Petrie in his , p. 353, ^{online at https://archive.org/details/ecclesiasticalar00petruoft} and by Zimmer in the Zeitschrift für Dentsches Altertum, vol. 35, p. 100.Zimmer's edition swarms with misreadings and misprints. Thus he has nifetad for nirofetad, nifiu for nirfiu, re Gallaib for re Gall dibh, fric for fris, Murchatu for Mucutu, on enleabad for a n-enleabaid, etc. But worse than these mistakes is the treatment to which he has subjected the stanza beginning M'éra-sa. He failed to recognize the metre in which it is composed, retained the late and faulty bérat-sa, made duine into dāine, and ended by incorporating part of the prose in his reconstruction, which will neither scan nor make sense! As neither edition is free from mistakes, I reprint this prose in extenso and add a version of my own. It is curious to find both Petrie and Zimmer believing in the authenticity of this late, confused, and on the face of it spurious account, and trying to reconcile its statements with historical facts, — Petrie, by giving to Gaill the unusual meaning Saxons; Zimmer, by boldly inventing a second poet Ruman as having lived during the Viking age.

Unfortunately, several words in the first stanza of the poem are no longer legible in the MS. As to the metre in which it is composed, see Thurneysen, , iii, p. 158.