The authors seek to identify the main specific features of the “Moscow as the Third Rome” concept (Philotheus) and its later interpretations, geopolitical as well, in modern Russia. The historical and interdisciplinary research conducted based on the source made it possible to propose a new vision of possible grounds for Russian foreign policy strategy. The “Third Rome” notion, from the perspective of its impact on Russian foreign policy and its geopolitical dimension, has been addressed in the works of many authors. It conveys both a historiosophic phenomenon, a national idea and the vision of a fair state. The concept, being in tune with the mood of Russian society, has had an impact on both the inner structure of the state and its foreign policy, which allows us to suggest that the concept of Moscow as the Third Rome may be considered Russia’s informal geopolitical doctrine. © 2018 Universidad Complutense de Madrid. All rights reserved.