For most Western observers, the Orthodox Church is a beautiful liturgical tradition of icons and choral music — not a serious factor in geopolitics. This is a mistake. Orthodoxy is the majority faith of roughly 260 million people, concentrated in a belt from Russia through Ukraine, Belarus, Serbia, Bulgaria, Romania, Greece, Georgia and parts of the Middle East. Unlike Roman Catholicism, it has no single leader; each national church is autocephalous (self-governing) under a loose primacy of the Ecumenical Patriarch in Constantinople (Istanbul). Since 2018, Orthodoxy has been in the deepest schism of its modern history, and that schism runs directly along the front lines of the Russia-Ukraine war. The story of Orthodoxy in the twenty-first century is inseparable from the story of Russia's attempt to redefine itself as a civilizational state at the head of an Orthodox world.
After Constantinople fell to the Ottomans in 1453, a Russian monk named Philotheus wrote to the Grand Prince of Moscow: 'Two Romes have fallen, a third stands, and a fourth there shall not be.' Moscow, the doctrine went, had inherited the mantle of universal Christian empire. This 'Third Rome' idea faded through the Petrine and Soviet centuries but never quite died. Under Putin and Patriarch Kirill of Moscow — a former KGB associate turned church leader — it has been systematically revived as state ideology. The Russian Orthodox Church operates as an arm of Russian soft power abroad: parishes and monasteries in the Balkans, Africa and the Middle East, media operations targeting other Orthodox nations, theological arguments that Western liberalism is a heresy against Christian civilization. Kirill has publicly blessed the 2022 invasion of Ukraine as a 'holy war' against Western decadence. This is not fringe rhetoric; it is the official position of the largest Orthodox church in the world.
In January 2019 the Ecumenical Patriarch in Constantinople granted the Ukrainian Orthodox Church a Tomos of Autocephaly — recognising it as an independent national church, no longer subordinate to Moscow. Kirill responded by breaking communion with Constantinople and its allied churches, tearing the global Orthodox communion in two for the first time in a thousand years. This was not a footnote to the Ukraine war; it was a preview of it. From Moscow's perspective, losing spiritual jurisdiction over Kyiv — the historic 'mother of Rus'' where Prince Vladimir was baptised in 988 — meant losing the religious foundation of the Russkiy Mir doctrine. If Ukraine could have its own church, it could have its own everything. Since 2022 the war has accelerated the exodus: parishes across Ukraine have transferred from the Moscow-linked Ukrainian Orthodox Church to the independent Orthodox Church of Ukraine, and the Kyiv government has moved to ban the former outright.
The schism reshapes politics far beyond Ukraine. Serbia's church remains close to Moscow, reinforcing Belgrade's tilt toward the Kremlin and complicating Serbia's supposed EU path. The Church of Greece and the Church of Cyprus sided with Constantinople and recognise the Ukrainian church, aligning their political posture more clearly with the West. Bulgaria, Romania and Georgia have hedged. In the diaspora, Russian-linked and Ukrainian-linked parishes in Western Europe and North America have split neighbourhoods and families. The Orthodox world is now, in effect, two competing communions arguing over the same theology, the same saints and the same liturgy. Understanding which side a national church is on tells you something important about how a country reads the war in Ukraine — and about which civilizational story it thinks it belongs to.