The rule of law, understood as ideology and legal rules, is believed to be a competitive advantage of Western civilization, supporting its sustainable development. Yet it can also be viewed as a social norm of citizens who respect the law and follow its commands. How does this social norm emerge in different societies? This question must be answered through the social history of the law in Western and non-Western societies from a comparative perspective. This paper outlines the main features of comparative socio-legal history and tests it on some significant historical examples. In the first part of the article, the authors propose a functional classification of legal systems into three ideal Weberian types—the law of judges, learned law, and the law of the authorities. It allows us to consider the origin of the social norm of the rule of law. In the second part of the article, the authors trace the transition from the ideal types to natural legal systems and identify the factors that determine the stability of the social norm of the rule of law where it originated.In the final part of the article, the authors conclude that, first, the social norm of the rule of law emerged in the societies where the law had been treated either as a means of resolving disputes (the law of judges) or as the rules of fair, correct conduct (learned law), for example, the Roman Republic, medieval England, continental Europe, and the Ottoman Empire. Secondly, the stability of the social norm of the rule of law seems to be explained by a "triangle" of factors, namely: 1) political competition where all participants understand the inevitability of compromise on the basis of the law, 2) law which is suitable for finding a compromise due to its internal merits, 3) a professional community of jurists who develop and apply law independently of the administration. Such a triangle is possible in any society where the law of judges or learned law prevails and where the majority of participants in the political process are ready to compromise based on the current law
