In Old English, passive-type constructions involving a copula and a passive participle could be used to express both events and states. Two different types of copula are found in these constructions: weorðan, meaning ‘become’ and wesan and beon, meaning ‘be’. There has been some dispute as to how the meaning of these copulas relates to the meaning of the construction as a whole, in both its eventive and its stative uses, and whether any of these constructions was grammaticalized in the sense that their meaning was non-compositional. We propose a semantic model that represents these constructions compositionally and test it against a selected corpus of Old English texts in order to address two questions: whether the data provide evidence of non-compositional meaning that would suggest grammaticalization, and whether other factors are also responsible for the choice of copula. Our analysis suggests that the attested Old English passives are fully compatible with a compositional analysis; we also discuss additional semantic factors that may be responsible for the lower frequency of passives with weorðan.