The paper is a case study investigating the nominal and adjectival morphology in the English text of bounds to S 179, a post-Conquest forgery. The aim of the study is to determine what linguistic means of authentication were applied by an eleventh- century forger who devised a text which was supposed to look 200 years old at the time of its production, as well as to search for modern features which give the forgery away, at the same time allowing an insight into early Middle English. The study represents research into “transitional”, post-Conquest English (Faulkner 2012) and the status of English under the Norman rule.