Agreement is the linguistic term for the phenomenon in natural human language that the shape of a word is dependent upon properties of another word. Recent research into the phenomenon of agreement has mainly been centered upon agreement on verbs. Agreement does also occur on non-verbal categories, like adjectives. Given that it is mainly verb-based, present theories of agreement do not account for agreement on these categories. In order to tackle this problem, the project will focus upon adjectival agreement asymmetries, i.e. cases in which adjectives display agreement in one syntactic context but not in another. These asymmetries are widespread among the languages of Europe. Such agreement asymmetries enable us to determine the contexts in which adjectival agreement is possible and those in which it is not. A general theory of agreement should account for the relation between specific agreement morphology and the syntactic context that it is paired with. The ultimate goal of this research is to formulate a unified theory of agreement that does not only accounts for verbal agreement, but also for adjectival agreement.