not formally have the force of law. It indicated the requirements for a successful legal claim. The edict therefore became the basis for extensive legal commentaries by later classical jurists like Paulus and Ulpian. The new concepts and legal institutions developed by pre-classical and classical jurists are too numerous to mention here. Only a few examples are given here: Roman jurists clearly separated the legal right to use a thing (ownership) from the factual ability to use and manipulate the thing (possession). They also established the distinction between contract and tort as sources of legal obligations. The standard types of contract (sale, contract for work, hire, contract for services) regulated in most continental codes and the characteristics of each of these contracts were developed by Roman jurisprudence. The classical jurist Gaius (around 160) invented a system of private law based on the division of all material into personae (persons), res (things) and actiones (legal actions). This system was used for many centuries. It can be recognized in legal treatises like William Blackstone's Commentaries on the Laws of England and enactments like the French Code civil or the German BGB. The Roman Republic had three different branches: Assemblies Senate Consuls The assemblies passed laws and made declarations of war; the Senate controlled the treasury; and the consuls had the highest juridical power. Post-classical law By the middle of the 3rd century, the conditions for the flourishing of a refined legal culture had become less favourable. The general political and economic situation deteriorated as the emperors assumed more direct control of all aspects of political life. The political system of the Principate, which had retained some features of the republican constitution, began to transform itself into the absolute monarchy of the Dominate. The existence of legal science and of jurists who regarded law as a science, not as an instrument to achieve the political goals set by the absolute monarch, did not fit well into the new order of things. The literary production all but ended. Few jurists after the mid-3rd century are known by name. While legal science and legal education persisted to some extent in the eastern part of the Empire, most of the subtleties of classical law came to be disregarded and finally forgotten in the west. Classical law was replaced by so-called vulgar law. Substance Concept of laws ius civile, ius gentium, and ius naturale – the ius