This book is a systematic analysis of a series of changes in key distinct areas of nominal syntax in mediaeval English, namely the definite article, adnominal genitives and the indefinite article. In each of these three domains, distinct successive stages of development are formally outlined in Old and Middle English, showing that the nominal syntax of mediaeval English can successfully be analyzed through the descriptive tools of modern syntactic theories. The observed developments are then evaluated against different explanatory frameworks for syntactic change, questioning the plausibility and necessity of accounting for the analyzed phenomena in terms of language contact.