The present paper considers the problem of determining the legitimation of Russian power within the context of the traditional archaic political culture. The problem is solved based on the material of the discovered medieval spatial and myth-heroic construct (Korsun, Kiev-Moscow). The fact of Putin's legitimization of the reunification of the Crimea as a sacred land is associated with the sacral sources of political power. To describe the myth-spatial scheme, the method of reconstruction based on the heroic political monomyth model is used. Mythohistory tells about the birth of a new world with the help of a heroic deed, through which the sacred space of the sources of power is constituted. An essential analogy between sacred space and mythological space is made in the paper. The structure of this mythohistory is "dual": originally Prince Vladimir I played the heroic role; he is correlated with the two loci of mythological space, Korsun and Kiev. There are mytho-constructs of the "first move": Vladimir victoriously enters Korsun and takes the sacred symbols out of it, and then his consciousness transforms, and Ancient Kiev becomes the transformed sacred center of the Russian world. Acting as the baptizer of the Russian Land, Vladimir is associated with the cross of Constantine, i.e. the heroic transformation of the political sphere is not symbolically completed. Then comes the "second move": the sacred ritual of "crowning", introction into political power of Ivan IV as a "real" Orthodox king. And here the third locus of the mythological space of the sources of Russian power, Moscow, is constituted. It is in Moscow that the hero completes his political transformation, and the Orthodox state obtains the symbolic form of Rome, becoming its Third Incarnation. The localized mythological space of Russian political power acquires its truly sacred characteristics: it becomes a landmark (Moscow is the land of true Orthodox faith), since the Third Rome is the correct and united Christian state, the image and likeness of the Kingdom of Heaven (and the Orthodox king's charisma is modelled by Christ's one), and, finally, the political-sacred essence of the mythical hero is comprehended. It is to this general sacral-spatial source of Russian power, constituted in the myth, that Vladimir Putin appeals in 2014. Identifying the Crimea and Korsun as Russian Orthodox shrines, he extrapolates this symbolic identity to the similarity of their political value - Moscow's unity of lands was laid under Vladimir the Holy, and is the basis of the Russian world order. Thus the traditional construct of sacred space serves for the ultimate myth-heroic legitimation of Russian power. Furthermore, this constant of Russian political culture served as the basis for the current legitimizing discourse of Putin.