Recently, started reading Gibbon's Decline and Fall of the Roman Empire. I discovered that the printed versions I had access to were abridged, but the entire book is available on line in PDF or more detailed forms.
One reason it is worth reading chapter by chapter is that abridements seem to convey different messages. Often the various editors want to highlight particular points Gibbon made and let other matters drop. From what I can tell reaching chapter 20, he had a full agenda.
Secondly, when I read Gibbon I wonder how he became aware of anything. He is quite detailed about many matters and he backs it up with footnotes. Often I discover he is quoting continuously from several sources, e.g., Cassius Dion for events in the second century. In the case of Dio or Dion, it is often not from his original text but a surviving abridgement or "epitome" compiled centuries later. What an irony. In some cases, I have to wonder if some of the more fantastic claims or accounts are glosses. But, I'll try to get back on message.
In some of the notes Gibbon cites Eusebius. Some of it is from his Ecclesiastical History and then some of it is from his more general chronology of ancient writers. In the 1914 edition of Gibbon the editor said that Eusebius takes issue with Paul the Apostle's chronology of Israel recorded in Acts. I thought I would track it down. Going on line I found this and quotes of his successor in ecclesiastical studies, Jerome the translator of the Bible from Hebrew, Syraic and Greek into the Latin, the document known as the Vulgate.
In the course of uncovering Eusebius and Jerome, I encountered a wealth of 4th and 5th century controversies and some Gibbon history too. It was Diocletian that was responsible for the Christian persecution prior to Constantine's Edict of Milan. And that Diocletian persecution was most effective in the east. Most historians say that the count of martyrs was much exaggerated just as were the sizes of armies and casualties in battles. But the Diocletian's method was very effective in that it attacked the physical institutions of the church. It demolished the churches, libraries, exiled officers. Books and bibles were burned. The Greek originals.
This made Jerome's position in the west key: translating for a sheltered but less versed in traditions population. Jerome corresponded widely and his letters are preserved, but also his introductions to various books of the Bible.
Here he is on Daniel:
The churches of the Lord Savior do not read the Prophet Daniel according to the Seventy interpreters, using (instead) the edition of Theodotion, and I don’t know why this happened. For whether because the language is Chaldean and differs in certain properties from our speech, (or) the Seventy interpreters were not willing to keep the same lines in the translation, or the book was edited under their name by some unknown other who did not sufficiently know the Chaldean language, or not knowing anything else which was the cause, I can affirm this one thing, that it often differs from the truth and with proper judgment is repudiated. Indeed, it is known most of Daniel and some of Ezra were written in Hebrew letters but the Chaldean language, and one pericope of Jeremiah, and also Job to have much in common with the Arabic language.
When I was a very young man, after the reading and flowery rhetoric of Quintilian and Cicero, when I had opened myself to the drudgery of this language and with much effort and much time I with difficulty had begun to pronounce the breathy and buzzing words, as though walking in a crypt to see a little light from above, I finally dashed myself against Daniel, and I was affected by such weariness that, sunken in desperation, I wanted to despise all (my) old work. Indeed, a Hebrew was encouraging me, and he was often repeating to me by his language "Persistent work conquers all," as in me (?) I saw an amateur among them, I began again to be a student of Chaldean. And so I might confess the truth, to the present day I am better able to read and understand than to pronounce the Chaldean language.
Therefore, I have shown these things to you as a difficulty of Daniel, which among the Hebrews has neither the history of Susanna, nor the hymn of the three young men, nor the fables of Bel and the dragon, which we, because they are spread throughout the whole world, have appended by banishing and placing them after the spit (or "obelus"), so we will not be seen among the unlearned to have cut off a large part of the scroll.I heard a certain one of the teachers of the Jews, when he derided the history of Susanna and said it to have been forged by an unknown Greek, to propose that which Africanus also proposed to Origen, these etymologies to come down from the Greek language: "to split" from "mastich" and "to saw" from "oak" (απο του σχινου σχισαι και απο του πρινου πρισαι). On which subject we are able to give this understanding to those of our own (language), as we might, for example say it to have said of the oak tree (ilice), "you will perish there (illico)" or of the mastic tree (lentisco), "May the angel crush you like a lentil bean (lentem)" or "You will not perish slowly (lente)" or "Pliant (lentus), that is, flexible, you are led to death" or anything which fits the name of the tree. Then he jested for there to have been so much leisure time for the three young men, that in the furnace of raging fires they played with (poetic) meter, and called in order all the elements to the praise of God. Or what miracle or Divine inspiration is it, either a dragon having been killed by a lump of tar or the tricks of the priests of Bel having been discovered, which things are better accomplished by the wisdom of a clever man rather than by the prophetic Spirit? When indeed he came to Habakkuk and had read (of him) having been carried off from Judea to Chaldea carrying a dish, he requested an example where we might have read in all the Old Testament any one of the saints to have flown with a heavy body and in a short time to have passed over so great a space of lands. To which, when one of us rather a little too quick to speaking had brought Ezekiel into the discussion (lit. "middle") and said him to have been moved from Chaldea to Judea, he derided the man and from the same scroll proved Ezekiel to have seen himself moved in the Spirit. Finally also our Apostle, namely as an erudite man and one who had learned the Law from the Hebrews, was also not daring to affirm himself taken away in the body, but was to have said "Whether in the body or out of the body, I do not know, God knows." By these and arguments of such kinds he exposed (or "accused") the apocryphal fables in the book of the Church.
Concerning which subject, leaving the judgment to the decision of the reader, I warn him Daniel is not to be found in the Prophets among the Hebrews, but among those which they titled the Hagiographa.
Since indeed all of Scripture is divided by them into three parts, into the Law, into the Prophets, (and) into the Hagiographa, that is, into five and eight and eleven books, which is not (necessary) to explain at this time.
And to those things of this prophet, or rather against this book, which Porphyry accused, the witnesses are Methodius, Eusebius, (and) Apollinaris, who, responding to his madness with many thousands of verses, I do not know whether they are satisfying to the interested reader. For which reason I entreat you, O Paula and Eustochium, pour out prayers for me to the Lord, so that as long as I am in this little body, I might write something pleasing to you, useful to the Church, (and) worthy to posterity. I am indeed not greatly moved by the judgments of the present, which on either side are in error either by love or by hate.
The division of the Hebrew Scriptures then, has been known by Christians for at least 1600 years. Promoting Daniel to a prophet, as in the case of Augustine, was first instituted to show that the ancients were aware of Christ's coming. Then it was used as a device for apocalyptic groups to pummel their enemies for a millenium or so. Need I say more?