Philotheus of Pskov (c. 1465–1542) was a Pskov monk who formulated the idea of "Moscow, the Third Rome." Three epistles, written around 1510–1523, gave the Muscovite state its central ideological formula.
His logic ran thus: the first Rome fell through pride and heresy. The second — Constantinople — accepted union with the Catholics at the Council of Florence (1439), was punished by the Turks, and fell in 1453. The third Rome, Moscow, remains the sole keeper of true Orthodoxy. "Two Romes have fallen, the third stands, and a fourth there shall not be."
The epistles were addressed to Grand Prince Vasili III, and their character is theological rather than political — Philotheus speaks of responsibility, not of grandeur. But the formula proved convenient to power: it served to ground Moscow's claims to a special role.
The idea had a long life: it was pressed into service to justify the Third Reich in its own variant, the Soviet mission, and present-day conceptions of a "special path." Philotheus wrote three pages — and they have been at work for five hundred years.