Roman law in the form of the legislation of the emperor Justinian has been studied in Western Europe since the end of the eleventh century in Bologna. It has had enormous authority - mostly on an informal basis, but bolstered by a strong ideology. Since 1900, the year in which the German civil code came into force, hardly anywhere in Europe has it been possible to speak of Roman law as a direct source of current private law. Nevertheless, it was - and still is - a ‘common frame of reference’ long before this expression was coined in the framework of European private law of the future. The Study of Roman Law in Its Intellectual Context. It is possible to distinguish at least three different ways of studying Roman law today. A first approach starts with actual legal problems. One can certainly ask about the historical background of these problems, but the actual problems remain the centre of attention. So Roman law is a kind of auxiliary tool for the understanding of modern private law. It is a treasury of legal ideas that can be put to use in solving today’s legal problems. Institutions of Roman law are detached from their original context and so take on an air of timelessness. Examples are the clauses that accompany the contract of personal security: the beneficium divisionis or the beneficium excussionis. The lex commissoria in the law of sale and of pledge is another example. This is the timeless and the ‘infallible’ part of private law, useful for understanding modern private law. This approach has its roots in the Historical School of German jurisprudence of the nineteenth century and appears to be totally ahistorical. But that is not necessarily so: see, for example, the impressive book by Reinhard Zimmermann. He deals with the general structure of the law of obligations and explains clearly its historical roots, starting with the elliptical texts of the Roman jurists and going on to the legal scholars of the nineteenth century, the German Pandectists, who built complex dogmatic structures on the basis of Roman legal texts. For real rights there is now a comparable work by Willem Zwalve. It explains the law of ownership and other real rights using examples from historical sources and comparative law.