The article summarizes historical and chronological surveys of researchers of chronology systems as an important component of the phenomenon of the Old Russian Chronicles. The chronological framework of the research includes the works of the scientists of the XVIII and the beginning of XXI century. Using the hermeneutics methodology, the author considers the annalistic works as specific stages of development of the text of some perfect annalistic work. The result of the analysis of the scientific works which are in varying degrees devoted to the study of Old Russian chronology, was the identification of a complex set of chronology systems used by ancient chroniclers — in the extant chronicles there were depicted four cosmogonic eras of Constantinople, the Byzantine-Bulgarian, Antiochian and Old Russian era in 5511 years from the Creation to the Nativity of Christ and four calendar styles — September, March, Ultramarch and Postmarch. The obtained data contribute to deeper knowledge of a complex set of chronology systems used by ancient chroniclers.