The concept of “identity” is widely used in the studies on the history of ethnic groups, nation states, confessional communities and various kinds of classes. “Identity” is one of the anthropological universalia, the use of which dramatically expanded the horizon of human sciences in the 20th century. The universal concept of “identity”, like the concepts of “mentality”, “cultural memory”, “historical consciousness”, “symbolic representation”, is designed to find and demonstrate distinctive features of human “social consciousness”. The interpretation of identity as social category implies that the basis of identity formation is the process of communication, interaction, which is determined by the “reciprocity of perspectives”. This process, in turn, suggests the existence of a common semantic horizon, a common horizon of the senses. Monotheistic religions, apparently, could be used not only to strengthen ethnic identity, but to instill the characteristics of a monotheistic culture. This phenomenon is clearly seen in the history of Christianity, in the Roman Empire and among the barbarians, the Celts and the Germans; and in the fate of Islam of the Arabian tribes, Iranians and Berbers. The communities that were converted to Christianity or Islam in the Early Middle Ages had very different cultures but they all gradually accepted the new mode of the interaction between people and the new fashion of the communication with the outside world constructed by monotheistic religion. The interaction between the Muslim and Christian cultures in the Middle Ages was an essential factor of the development of religious identities and of the social space in general, which was characterized by interculturality. The interculturality of the social space gave an additional and very significant impulse to the cultural and social consciousness. The interaction of cultures based on different monotheistic confessions lead to creation of a broad communicative horizon shared by different confessional communities.