All communist states have been established in countries with a civil law system. The countries of Eastern Europe had formally been governed by the Austro-Hungarian Empire, German Empire and Russian Empire—all of whom had civil law legal system. Cuba had a civil law system imposed on them by Spain while China introduced civil law to overlay with Confucian elements and Vietnam used French law. Since the establishment of the Soviet Union, there has been a scholarly debate on whether socialist law is a separate legal system or is a part of the civil law tradition. Legal scholar Renè David wrote that the socialist legal system "possesses, in relation to our French law, particular features that give it a complete originality, to the extent that it is no longer possible to connect it, like the former Russian law, to the system of Roman law." Similarly, Christoper Osakwe concludes that socialist law is "an autonomous legal system to be essentially distinguished from the other contemporary families of law." Proponents of socialist law as a separate legal system, have identified the following features: