This study focusses upon the Old Norse version of Ælfric's Old English homily De falsis diis - the most substantial of a family of Old Norse-Icelandic texts, of unclear provenance, but which derive in varying degrees from Old English originals. To throw fresh light upon the translation's origins, a range of other Old Norse and Old English texts are considered. While the known facts of Ælfrician manuscript circulation and adaptation are hard to reconcile with an Icelandic origin, traces of later circulation in Norway and Iceland are explored. The study includes a parallel-text Old English-Old Norse edition of De falsis diis, with facing modern English translations, to aid detailed comparison.