A Secret Gospel in the Library of Eusebius at Caesarea

 Every time someone confidently says, “Well obviously Morton Smith must have smuggled the Voss book with a forged Clement letter into Mar Saba – that’s the only way a ‘fifth gospel’ could appear in an old ecclesiastical library,” I want to hand them Photius and a stiff drink.

Because the scenario “fifth gospel sitting quietly in a famous Palestinian library” is not some 20th-century fantasy. It’s literally a late–antique trope. And in one case it’s pointed straight at Jerome.

Here’s the core passage, from Photius’ Bibliotheca (summary of a work of “Theodore of Antioch” – i.e. Theodore of Mopsuestia – Against Those Who Say that Men Sin by Nature and Not by Choice). I’ll paraphrase the key part:

Theodore is attacking some Western heresy. He says its founder, starting in the West, travels around the East spreading his new doctrine. This man, Theodore says, “devised a fifth Gospel,” forged it, and “put it into the libraries of Eusebius of Palestine.” He also rejected the “divine and ancient Scripture,” meaning the Septuagint, as well as Symmachus, Aquila, and the other standard Greek versions, and instead produced his own private text – even though he wasn’t raised in Hebrew or trained in the sense of Scripture, but had only sat at the feet of a few cringing Hebrews and gotten enough confidence from them to publish his own version.

Theodore can’t quite tell whether the man is called or surnamed “Aram,” but the identification is straightforward:
Theodore of Antioch = Theodore of Mopsuestia.
“Aram” = Jerome.

Why Jerome? Because Theodore is clearly reacting to Jerome’s anti-Pelagian material. And in that Pelagian context Jerome himself mentions a special Gospel in Caesarea.

In Dialogue Against the Pelagians (3.2), Jerome famously says that in the Gospel according to the Hebrews – “written in the Chaldee and Syrian language, but in Hebrew characters,” used by the Nazarenes, “a copy of which is in the library at Caesarea” – he finds sayings of Jesus not in our canonical Matthew. Jerome explicitly claims:

– There is a Hebrew/Aramaic gospel text,
– used by a Jewish-Christian group,
– and a copy of it is preserved in the library at Caesarea.

Now put Photius and Jerome side by side.

Jerome says: I’ve seen a special Gospel according to the Hebrews in the library at Caesarea and I cite it as a source.

Theodore (as summarized by Photius) says: This Western heresiarch, “Aram,” concocted a “fifth Gospel” and inserted it into the libraries of Eusebius of Palestine, and he also set up his own text against the ancient versions.

In other words, from Theodore’s side the whole Jerome-and-the-Hebrew-Gospel thing looks like a heretic manufacturing a new Gospel and sneaking it onto Eusebius’ shelves. The crime is not just doctrinal; it’s curatorial. You’re not only teaching bad theology, you’re messing with the library.

You don’t have to believe Theodore’s polemic to notice what it presupposes:

1. That it is entirely imaginable for there to be “a fifth Gospel” in a major Palestinian library.

2. That locating such a Gospel specifically “in the library of Caesarea” is already a known claim (Jerome’s).

3. That one can weaponize that claim polemically by saying the heretic “forged it and put it in the libraries of Eusebius.”

This is why appealing to “but surely nobody would ever smuggle/insert a gospel into a venerable monastic or patriarchal library!” as a knock-down argument against Secret Mark is so weak. Late–antique authors were already talking exactly that way – only in their story the culprit is Jerome.

And notice how fast modern people slide from “logistically possible” to “therefore he did it.” In the Mar Saba debate, the argument for Smith’s supposed smuggling often boils down to something like:

– He was an authorized guest;
– Monks weren’t TSA;
– Therefore he could have carried in Voss with a pre-inscribed fake Clement text;
– Therefore he did.

Meanwhile, people who actually spent time in the Jerusalem Patriarchate environment – Quesnell, Tselikas – say some version of “it’s not that simple” and suggest he’d have needed an accomplice, access patterns, trust networks, and so on. You can agree or disagree with them, but at least they’re talking from experience of that ecosystem rather than a theoretical airport-security model.

What I find more interesting is that the genre of accusation is old. Theodore vs. Jerome is already playing the same game. You don’t like a guy’s exegesis? Fine, accuse him not only of bad doctrine but of forging a Gospel, making up his own biblical text, and slipping it into a famous library under false pretenses.

It’s the same rhetorical toolbox that gives you:

– Carpocrates using “magic” to overcome a presbyter and get his copy of the gospel.
– Followers of Mark the magos allegedly enchanting wealthy women and emptying their purses.
– Epiphanius reporting that certain sects drink menstrual blood.
– Marcionites supposedly worshipping snakes.
– Heretics branding each other with hot irons.

None of this proves Jerome really forged anything. It proves that church writers were perfectly willing to narrate their enemies (or rivals) as doing wild, quasi-criminal things with books, bodies, and sacred spaces.

So when someone tells you that the very idea of a “fifth gospel” living quietly in a Palestinian library is absurd on the face of it, or that “no one would ever slip a suspect text into such a collection,” Photius is sitting there waving.

From Theodore’s point of view, the precedent already exists:

There was a fifth Gospel.
It was linked to a major library.
It was tied to Jerome.
And the whole thing could be framed as a forgery, deliberately planted among the books of Eusebius.

You don’t have to buy Theodore’s story to see what it does to the modern rhetoric. It doesn’t prove Secret Mark is authentic. It does undercut the lazy confidence that “these things just don’t happen” – that the only way to imagine an extra gospel in a holy library is to invent a 20th-century smuggling caper. The ancient sources were already there, accusing each other of exactly that sort of thing, long before Morton Smith ever set foot in Mar Saba.