This article looks at the role of deflexion in the development of the genitive in English and offers an empirical base for evaluating some claims which have been made about how this development proceeded. It focuses primarily on the claim that it was impossible for the genitive to remain as a morphological case once the other case distinctions were lost in the nominal system. This claim is based on a dubious typological argument and evidence is presented that the genitive retained some inflectional characteristics in Middle English. The article also looks at how the so-called ‘his genitive’ found in some earlier texts fits into the general picture of the development of English possessives.