If one reads Eusebius through the lens of Nicene orthodoxy alone, his treatment of the evangelists looks merely traditional. But if one allows for the possibility that Eusebius’s ecclesiastical history is shaped by Alexandrian—and specifically Boucolian—memory, then the asymmetry you are pointing to stops being accidental and starts to look strategic.
On this reading, Eusebius’s privileging of Mark is not simply antiquarian. It reflects a theological and institutional alignment. Mark is not just an evangelist; he is the founder-symbol of the Alexandrian church, and more precisely of the Church of St Mark in the Boucolia, the very ecclesial space with which Arius and his supporters were associated. To favor Mark, narratively and structurally, is to favor Alexandrian apostolic legitimacy over later episcopal monopolies.
This helps explain why Eusebius treats Matthew and Luke as texts but Mark as a person-in-history. Matthew is reduced to an ethnic-linguistic datum: written “among the Hebrews,” in their dialect. Luke is absorbed into Pauline authorship and literary orderliness. Neither is tied to a living ecclesial site that matters to Eusebius’s present. They are safe, inert, already canonized.
Mark is different because Mark anchors a rival apostolic genealogy—one not mediated through Rome, Antioch, or Nicene episcopal succession, but through Alexandria. When Eusebius narrates the origin of Mark’s Gospel, he does so by staging a scene in which authority flows upward from the people and laterally from apostolic approval, not downward from episcopal command. Peter does not commission; he does not dictate; he does not control. He merely refrains from stopping what has already happened. That detail matters. It strips Petrine authority of its coercive force while preserving its symbolic presence.
From an Arian-friendly Alexandrian perspective, this is exactly what one would want. The Boucolian church traced its legitimacy not through doctrinal formulations imposed by councils, but through ancient preaching, communal fidelity, and inherited tradition. Mark, as Eusebius presents him, embodies that model perfectly. He is not a theologian of essence; he is a recorder of proclamation. His gospel arises before dogma, before metaphysics, before creeds. It is therefore usable—indeed preferable—for a theological movement that resisted Nicene ontologization of Christ.
This also clarifies why Eusebius does not bother to historicize Matthew or Luke. They are not useful symbols for this project. Matthew is too easily co-opted by Judaizing or proto-Nicene frameworks of fulfillment. Luke is too closely bound to Paul and to an emerging catholic synthesis. Mark alone can be framed as pre-dogmatic, pre-creedal, and pre-imperial.
Seen this way, Eusebius’s Mark is not merely earlier; he is purer. Not in the modern text-critical sense, but in the sense of standing closer to the moment before theology hardened into ontology. That is precisely the Christological space Arius sought to defend: a Christ proclaimed, not defined; exalted, not consubstantialized.
The Boucolian context sharpens this further. The Church of St Mark was not just a building; it was a counter-memory within Alexandria, opposed to the episcopal establishment centered elsewhere in the city. By foregrounding Mark as the foundational evangelist and Alexandrian missionary, Eusebius supplies that church with an apostolic pedigree that bypasses later episcopal claims. Mark becomes the warrant for a Christianity that predates and relativizes Nicene authority.
So the difference you have identified is not merely literary. It is ecclesiological and theological. Eusebius does not need to explain Matthew or Luke because they belong to a settled, uncontested tradition. He needs to explain Mark because Mark is the load-bearing figure for an alternative apostolic memory—one that an Arian-leaning historian of the early fourth century would have every reason to preserve, protect, and quietly privilege.
In that sense, Eusebius’s Mark is not just the first evangelist. He is the evangelist of a church whose legitimacy Eusebius still has reason to defend.
