Kaluza’s law is a proposed restriction in the metre of Beowulf against the resolution of light-heavy sequences: words like cyning ‘king’ can only resolve and count as the equivalent of a single heavy syllable under more restricted circumstances than can words such as wudu ‘wood’. There has been debate about how to define these ‘restricted circumstances’, with many investigators claiming that this limitation holds only under ‘secondary stress’ (sometimes broadened to include subordinated stress in general). This article reviews the operation of Kaluza’s law in Beowulf, arguing that the correct conditioning is the position immediately following a heavy syllable. The level of stress carried by the (non-)resolving sequence is irrelevant. A phonological explanation for this restriction may be that the resolution ideally produces bimoraic (light-light) units; accordingly, resolution of light-heavy sequences, which is anomalous from a typological and phonological perspective, is only permitted in word-initial position, or in metrical equivalents.