This paper examines subject-verb agreement in Early-Irish sentences with coordinate subjects. We claim that Early Irish (Old and Middle Irish) is a ‘variable agreement’ language, which exhibits both singular and plural agreement with coordinate subjects. The type of agreement depends on adjacency between subject and verb and the valency of the verb. In particular, unaccusative and passive verbs exhibit both singular and plural agreement more frequently than transitive verbs. We argue that this is due to the availability of a default third person singular null locative expletive item, which controls singular agreement. Moreover, unaccusative and passive verbs also allow locative inversion with other PPs, leading to the same singular agreement. Furthermore, we suggest that, in contrast to Modern Irish, which lacks such an expletive, Early Irish could license its presence in intransitive/passive sentences because that stage of the language exhibited EPP-effects