In Ancient Greek, as well as in other languages, whenever agreement is triggered by two or more coordinated phrases, two different constructions are allowed: either the agreement can be controlled by the coordinated phrase as a whole, or it can be triggered by just one of the coordinated words. In spite of the amount of information that can be read on this topic in grammars of Ancient Greek, much is still to be known even at a general descriptive level. More importantly, the data still lack a convincing explanation. In this paper, we focus on a special domain of agreement (subject and verb agreement) and on one morphological feature that is expected to covary (number). We discuss the agreement in number for conjoined phrases, by revising some of the modern hypotheses with the support of the empirical evidence that can be collected from the available syntactically annotated corpora of Ancient Greek (treebanks). Results are interpreted according to syntactic features, cognitive factors and semantic properties of the coordinated phrases.