Since the Vikings clashed with Western European civilization, they have been in the focus of European history. From the 9th to the 11th century, the Vikings received much attention in Western European Christian chronicles and annals. From the 13th century with the spread of written language in Scandinavian countries the sagas and tales of the heroic epos about the Vikings were recorded, but from the 14th century, the focus of European history changed, the study of Vikings in the period from the 14th to the 19th century was sporadic. In connection with the formation of history as a science in the middle of the 19th century, there was a new stage in the study of the Vikings. To designate the Normans and the chronology of their actions, the definitions of ‘Viking Age’ and ‘Vikings’ were introduced, but there is still no single approach to the interpretation of these key definitions in historical science. Taking into account such a chronological range in the study of Vikings, the genesis and methods of interpretation of the key definition of Vikings study nowadays are analyzed in the paper. The goal of the paper is to study the problems of the definition of the ‘Viking Age’ in modern historiography. The objective of the paper is to find out the links between the approaches and methodological principles of the ‘Viking Age’ definition interpretation. In modern historiography, there are three main interpretations of the definition of the ‘Viking Age’ and related approaches to the study of the subject matter. Firstly, the ‘Viking Age’ as one of the stages of specific national history in the Middle Ages. Historians using this interpretation rely on a unitary-stage approach and methodologically use Ferguson’s theory of stage typology. Secondly, the ‘Viking Age’ as an integral part of the European Middle Ages, which is not a separate period. Such a characteristic is typical of the supporters of Marxism. Thirdly, the ‘Viking Age’ as a separate period in the European Middle Ages. This interpretation is typical of plural-cyclical approach supporters.