Although the lexicon has frequently been used in discussions of the dating of Old English poetry, little attention has been paid to the evidence that poetic simplexes offer. One exception is an article by R. J. Menner, who noted that Beowulf and Genesis A share three poetic words, apart from compounds, that are not found elsewhere: freme ‘good, valiant’, gombe ‘tribute’, and secg ‘sword’. Menner used these words as part of an argument for an early date of Genesis A, an argument which hinged, in part, on lexical similarities between this poem and Beowulf, which he assumed was early. Although such an a priori assumption is no longer possible, evidence provided by the limited distribution of certain poetic simplexes is nonetheless useful for demonstrating the presence of a connection between two or more poems. Such a connection may be a matter of date or dialect, or it may indicate that the poems were the products of a single poetic school or subtradition. Unfortunately, we know little, if anything, about poetic subtraditions, and the poetic koiné makes the determination of the dialect of individual poems a complex and subtle matter that requires a much wider variety of evidence than poetic words can provide. However, the limited distribution of certain poetic simplexes can serve as an index of the poetic conservatism of the poems in which these words occur. This conservatism could be due to a number of factors: genre, content (that is, heroic legend vs biblical or hagiographical), style, or date of composition. As will emerge in the course of this discussion, the most straightforward explanation for this conservatism is that the poems which exhibit it were composed earlier than those which do not. Other explanations are, however, possible, and the evidence of poetic words is hardly sufficient by itself to determine the dating of Old English poems. But by focusing on patterns of distribution that centre upon Beowulf, we can examine what certain words may tell us about the conservatism of this poem and of those poems which are connected to it.