I examine those linguistic features of Old English and Old Norse which serve as the basic elements for the metrical systems of those languages. I begin with a critical survey of recent work on Old English metrical theory in chapter 1, which suggests that the four-position and word-foot theories of metre are the most viable current frameworks. A further conclusion of this chapter is that stress is not, as is often claimed, a core element of the metre. In chapter 2, I reassess the phonological-metrical phenomenon of Kaluza's law, which I find to be much more regular and widely applicable within Bēowulf than has previously been recognized. I further argue that the law provides evidence that Old English phonological foot structure is based on a preference for precise bimoraism. In chapter 3, I examine the role of syllables in the Norse Eddic metre fornyrðislag, which supports a view of resolution and phonological feet similar to that found in Old English, though Norse prosody is much more tolerant of degenerate, light feet. I reconsider the other major Eddic metre, ljóðaháttr, in chapter 4, integrating the insights of Andreas Heusler and Geoffrey Russom to propose a new system of scansion for this notoriously recalcitrant verse form. This scansion provides important support for the word-foot theory, and suggests that linguistic elements larger than syllables or phonological feet play a crucial role in early Germanic verse. In the final chapter, I give a diachronic account of Germanic metre and relevant linguistic structures, arguing that the word-foot theory provides the best metrical framework for understanding the development of Germanic alliterative verse. This metrical system is linguistically supported by Germanic word structures and compounding rules, and interacts with bimoraic phonological feet, all of which have a long history in Proto- and pre-Germanic.