The volume presents the Byzantine idea as it was perceived and expressed by two eminent thinkers in the historical and philosophical thought of Russia in the second half of the 19th century. Here are two extremely relevant essays: "Byzantinism and the Slavs" (1875) by Konstantin Leontiev and "Byzantinism and Russia" (1896) by Vladimir Solovyov. These authors are not the most typical, but undoubtedly the most interesting representatives of the Slavophiles and the Westernizers, respectively. They represent the two main intellectual currents of that period, which coexisted in inseparable unity but also in conflict with each other. Because, as Alexander Herzen said, although they may have looked - like Janus or the Double-Headed Eagle - in opposite directions, they all had a beating heart. The confrontation between the Slavophiles and the Westernizing intellectuals defines, in an aesthetic and emotional way at least, the entire cultural and political course of Russia up to our own days. Byzantium, beloved or hated, played a decisive role in shaping Russia, from its birth to the moment it became an imperial superpower, a crucial geopolitical factor.