The article aims to investigate the domestic historical and legal experience of regulating the mechanism of the transfer of supreme power through the prism of the formation and evolution of institutions of the heir of supreme power, co-ruler (successor) and successor of the throne. The purpose of the study is to identify the specifics of the legal institutions of the co-ruler (successor) and successor of the throne, used in cases where it is impossible to transfer the supreme power by inheritance, as well as their role, significance and place in the mechanism of reproduction of the supreme state power. The object of the study is the legal mechanism of the transfer of supreme power in the history of Russian law, from the formation of a centralized state to the liquidation of the monarchy, the subject is the legal institutions of the heir, co-ruler (successor) and receiver of supreme power as independent components of the mechanism of the transfer of supreme power. The institutions of the co-ruler and receiver of the throne are considered in the context of the reception of the norms of Late Roman and Byzantine law, the legal structure of the receiver of the throne, dating back to canon law, is investigated. Guided by formal-logical, historical and comparative-legal research methods, based on historical and legal sources, it is concluded that in the case of a non-hereditary transfer of monarchical power in Russian law, the institution of the successor of the throne, which took shape in the legislation of the XVIII century, operated. The successor of the throne was opposed to the heir according to the criterion of the legal basis of the rights to the throne. The content of the institute of co-rule reveals the Russian specifics, consisting in a combination of signs of Byzantine co-rule and late Roman succession, which was due to the transition from the ancestral (ladder) order of succession to the family (from father to son) during the formation of the Russian centralized state. In the era of absolutism, the institution of a co-ruler (successor) of the supreme power is displaced from the sphere of legal regulation and subsequently develops only as a political institution.