Do We Know Exactly Which Books Were Inside Constantine's Fifty Copies?

Evidence: Eusebius, Life of Constantine 4.36

What the ancient record says

No, and this is where people move beyond the evidence. The letter orders fifty copies of the sacred writings needed for the assemblies but does not provide a table of contents listing every work.

So: cannot say "Constantine ordered exactly the modern 66-book Bible" (not proven); cannot say the fifty definitely contained every work in a modern 88-scroll collection (not proven); cannot identify Codex Sinaiticus as one of the fifty with certainty (discussed historically, not established, similar date/context is not enough without a direct chain). What we know: Constantine ordered fifty copies; Eusebius arranged them; intended for assemblies associated with Constantinople; professional production expected.

What we do not know from the letter: the complete contents of each codex. "unknown" matters, honest history is stronger when it refuses to fill gaps; the commission is fascinating enough without turning the missing table of contents into a conspiracy theory.