This paper starts from charters. It may even be regarded as an attempt to trace and explain the rise and development of express warranty clauses in English private documents, an exercise in diplomatic. The main stimulus behind the investigation is, however, something quite different: the challenge of understanding English law before the advent of a common law. I want my explanations to be consistent not merely with the social relations that produced the charters, but also with the mental terms in which they were thought out and interpreted, their legal context.