Why did one monk derail the most ambitious attempt to unify East and West?

Ideas & Philosophy · Published 3 October 2026 Swipe more like this →

In short: Mark of Ephesus was a central figure at the Council of Florence, initially favoring union between the Orthodox and Catholic Churches. Yet, he became the primary architect of its failure, refusing to sign the final agreement and cementing his legacy as the defiant Atlas of Eastern Orthodoxy.

Born Manuel Eugenikos in 1392, Mark was a scholar and hesychast theologian who rose to become the Metropolitan of Ephesus. His early life was defined by rigorous education under figures like Gemistus Pletho, and he entered the 1438 Council of Ferrara–Florence as a key delegate. Initially, Mark was open to the prospect of union, but his stance shifted as he engaged with Latin theological arguments and perceived procedural suppression of the Ecumenical Councils.

The core of the conflict lay in the Filioque clause—the Latin addition to the Nicene Creed—and the doctrine of Purgatory. Mark rejected the Latin assertion that the Holy Spirit proceeds from both the Father and the Son, viewing it as a theological innovation inconsistent with ancient dogma. His opposition was not merely abstract; he was a master of practical apologetics, highlighting cultural differences like the Latin use of unleavened bread and the shaving of priests' faces to rally the Greek populace against the union.

Interestingly, Mark’s intellectual profile was complex. While he famously clashed with Latin theology, he was not ignorant of it. Scholars have noted his sophisticated, if selective, use of Latin authorities like Augustine of Hippo and Bernard of Clairvaux to bolster his own arguments. He even appears to have utilized Thomas Aquinas’ hylomorphic framework to defend the doctrine of the Resurrection against Platonist critiques, demonstrating a nuanced, albeit polemical, engagement with Western thought.

Mark died in 1444 at age 52, leaving behind a legacy that would eventually lead to his canonization in 1734. His refusal to sign the Council’s documents effectively doomed the union, and he spent his final years urging his followers to defend the Orthodox faith. Today, he is remembered as a Pillar of Orthodoxy, a figure whose intellectual rigor and uncompromising stance defined the boundaries between the two traditions for centuries.

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