It takes its name from Max Kaluza, who made an influential observation on the metrical characteristics of unstressed syllables in Beowulf.
Like other Old Germanic-language alliterative verse, the Old English poetic metre of Beowulf exhibits the phenomenon of resolution, whereby, under certain conditions, two syllables count as one for metrical purposes.
R. D. Fulk developed Kaluza's observations to argue that they show that at the time when Beowulf was composed, poetic varieties of Old English still distinguished between long and short vowels in unstressed syllables.
Most linguists who have considered Kaluza's law hold that the patterns in Beowulf reflect a phonological constraint in early Old English poetic metre.
However, several scholars have argued that the appearance of Kaluza's law patterns in Beowulf specifically may not reflect the continued distinction between long and short vowels in unstressed syllables at the time of Beowulf's composition, but a residual conformity to older patterns arising from any of a range of postulated factors, including:[5]: 659–660 Leonard Neidorf and Rafael J. Pascual contend that these alternative explanations are weaker than the phonological explanation preferred by Kaluza and Fulk.