Which city was referred to as a '3rd Rome'?

Moscow was referred to as the "3rd Rome" based on a historical and cultural narrative that emerged in the context of Orthodox Christianity. After the fall of Constantinople to the Ottoman Empire in 1453, many in Russia viewed Moscow as the legitimate successor to the legacy of the Byzantine Empire (often considered the "2nd Rome"). This idea was rooted in the belief that the Russian Orthodox Church, which became increasingly dominant in Moscow, inherited the responsibilities of defending the faith and the true Christian empire.

The term "3rd Rome" encapsulates the notion that Moscow, as the center of Orthodox Christianity and the seat of the Russian Tsar, was destined to carry forward the spirit and religious authority of Rome and Constantinople. This narrative was further solidified by various religious leaders and scholars in Russia who emphasized Moscow's role in preserving the Orthodox faith and culture. Thus, the designation of Moscow as the "3rd Rome" reflects its significance in the historical and religious context of Eastern Orthodoxy.