The argument of this Article is based on positivist postulates (principally from Hart) defining law as the union of primary rules (social norms) and secondary rules (of recognition, change and adjudication). Taking the presence of rules of change to be decisive for the appearance of legal orders, the author first looks for their origins in the Western world. Romans were the first, in the Western world, to develop a legal system with a clear rule of change, the possibility of a new statute abrogating an old one. This Western concept of law has been exported by Western colonialism to America, Asia (especially India), and Africa, transforming social (and customary) rules into laws thanks to the use of a Roman frame. While Jewish, Chinese and Islamic legal systems also fit this definition, their rules of change were not identical to the Roman ones (because of their stress on interpretation rather than direct change). However, these other systems were not as successful as Roman law, which was linked historically with imperialism and colonialism.