New Rome is a term that can be applied to a city or a country. It can be used to express connection with or discontinuity from the "old" Rome, depending upon context. New Rome has been a cultural, historical, and theological concept within much of Western culture (as far east as Russia) for centuries if not millennia. The term "New Rome" can be used as insult and as praise. Its oldest use may be in reference to Constantinople, since Nova Roma or Νεα Ρωμη was an alternate name for the city. This particular New Rome served as the capital of the Roman Empire from the 4th century until the fall of the Western empire and for nearly a millennium afterwards for the Empire as it survived in the east. In 451 the Council of Chalcedon gave New Rome and its Patriarch equal ecclesiastic status with Old Rome.
New Rome in the "East"
As Nova Roma, Byzantine writers contrasted their city from the "old" Rome by pointing out how Byzantium had always been a Christian city, while Old Rome had pagan roots. Polemical writings after the Great Schism even claimed that Old Rome was too stained by the blood of martyrs to lead Christianity. To the present day, the Patriarch of Constantinople includes "of Constantinople, New Rome" in his full title.
Moscow as the "Third Rome"
Within decades after the Fall of Constantinople in 1453, some were nominating Moscow as the "Third Rome", or new "New Rome". Stirrings of this sentiment began during the reign of Tsar Ivan III, but the idea crystallized with a panegyric letter composed by the Russian monk Filofei in 1510 to Tsar Vasili III , which proclaimed, "Two Romes have fallen. The third stands. And there will not be a fourth. No one will replace your Christian Tsardom!"
Since Roman princesses had married Tsars of Moscow, and, since Russia had become, with the fall of Byzantium, the most powerful Orthodox Christian state, the Tsars were thought of as succeeding the Byzantine Emperor as the rightful ruler of the (Christian) world. The word "tsar," like kaiser, is derived from the word "caesar". This "Muscovite Third Romism" persisted into the Bolshevik era of the Soviet Union, when Nicolas Berdyaev wrote, "Instead of the Third Rome in Russia, the Third International was achieved and many of the features of the Third Rome pass over to the Third International." Some scholars have seen Muscovite Third Romism as the Russian equivalent of the USA's Manifest Destiny, and other concepts used to rationalize imperialism.
New Rome in the "West"
On the other hand, for countries that underwent the Protestant Reformation, "New Rome" became a pejorative description, applied to nations or cities that earned a reputation for rapacity, immorality, or other social or political faults. This may have its roots in virulently anti-Roman propaganda against "papists" and the city of Rome, home of the Pope and heart of the Roman Catholic Church, which drew the ire of many a Reformation author. In the present day, "New Rome" is used in this form mostly to refer to "political immorality", casting any large and powerful country into the role of an oppressive and expansionistic empire. "Babylon" is used in a similar sense.
Dmytryshyn, Basil (transl). 1991. Medieval Russia: A Source Book, 850-1700. 259-261. Harcourt Brace Jovanovich. Fort Worth, Texas.