In this paper, I argue that quantitative data on relative clause variation in Old English provide additional evidence against the theory of multiple authorship of Beowulf. I show that aspects of various relative clause types in Beowulf are unique in the Old English poetic and prose corpus and homogenous throughout all three proposed parts of the poem. Comparison with the poems attributed to Cynewulf indicates that the frequency, distribution, and selection of relative clause types are consistent throughout an individual poet's compositions. Statistical analysis of the general distribution of relative clause types and factors such as the type of antecedent and its distance to the relative clause supports the hypothesis that Beowulf is a unified poem.I would like to thank R. D. Fulk, Kari Ellen Gade, and Rex A. Sprouse for comments and critiques of drafts of this paper, and audiences at “Studies in the History of the English Language I” at UCLA and “Philology in Germanic Studies at Illinois and Indiana V” at the University of Illinois for helpful discussion. Special thanks to Julie Auger for advice and her generous help with the VARBRUL analysis. Any remaining errors are of course my own.