In a piece I posted on this blog in August, I mentioned that my search for traces of the missing books of Livy went cold, very cold, in the late 6th century. I feel a little silly now, reading L D Reynolds' introduction to Texts and Transmission: A Survey of the Latin Classics,a collaborative work of 14 Classical scholars which describes the most important known manuscripts of the texts of 134 ancient Latin texts and the ways in which the printed versions of those texts came to be made from those manuscripts, and learning that Livy is absolutely typical of ancient Latin authors in this regard: many of their texts disappeared around that time. The 7th century represents the darkest of the Dark Ages when it comes to the transmission, the passing down, of ancient Latin texts. As Reynolds puts it on p xv, referring to nothing else but the transmission of ancient Latin: "By the time the sixth century had reached its mid-course the Dark Ages had come, and they seem to have come with a vengeance." On p xvi he illustrates his point with some striking figures: we possess only 264 7th-century Latin manuscripts, even defining the 7th century very generously to include manuscripts which may have been made either in the late 6th or early 7th century, or in the late 7th or early 8th century. 264 is a tiny number compared to the number of manuscripts from later centuries. For example, there are 330 15th-century manuscripts just of the work of the author Sallust. Of those 264, only 26 are secular, that is, something other than books of the Bible or Christian prayers or theology or things which otherwise have to do with Christianity. Of those 26, 8 manuscripts have to do with law, 8 with medicine, 6 with grammar and 1 with surveying, 1 contains excerpts from Vegetius' book on military matter, 1 was made in Spain and is a miscellany of mostly Spanish authors, and 1 contains a fragment of Lucan's poem about the Civil War in late republican Rome.
That's all 26. 24 manuscripts of very little literary interest, 1, the Vegetius, of middling literary interest, and then Lucan, usually classed as a minor classical author. As I was reading p xvi I kept saying to myself, "[...]and a palimpsest of Gellius. And Gellius. There's a 7th-century manuscript of a fragment of Gellius' work," but no. Professor Ihm, in the apparatus to his 1901 edition of Gellius (an author who to this day, like Lucan, is read somewhat more often and with more enjoyment than, say, Vegetius.), an edition with which I was familiar, describes the palimpsest manuscript, Vatican pal Lat 24, as "s VII (?)." Ihm was guessing that this was a 7th-century manuscript and making it clear that this was a guess. P K Marshall, in Texts and Transmission, published in 1983, says it was made in the 4th century, no ifs, ands or buts about it (p 176). I believe that the experts got much better at dating manuscripts between 1901 and 1983, and that we can trust Professor Marshall when he says that Vatican pal Lat 24 is a 4th-century manuscript. I don't know enough about paeleography to tell you in any detail why I think it's safe to go ahead and trust Marshall on this issue, but I do. Trust me, or look into these things for yourself. (I hadn't realized it, but Vatican pal Lat 24 is the very same manuscript which also contains the palimpsest passage of book 91 of Livy which I've mentioned a few times in this blog, and some other noteworthy palimpsest classical fragments as well.)
Marshall's clarification of the date of this, the oldest known manuscript of Gellius, is very much a mixed thing: from a purely practical point of view, with a concern for re-creating a text of Gellius which is as close as possible to what the author intended to say, 4th century, all other things being equal, is much better than 7th century. All other things being equal when it comes to establishing the text, older, closer to the time of the original composition, is better. And 4th century is much older than 7th from an editor's point of view.
On the other hand, there are so many 4th century manuscripts of the Latin classics laying around, and so few from the 7th century. And, it turns out, one less than I had thought until now. 7th century manuscripts of the classics are like black swans. If you think of it as classics versus Christians, and there are plenty of good reasons to think of it that way, then a 7th century manuscript of a classical author is a treasure rescued from the belly of the beast, from the very center of the darkness of the Dark Ages. 4th century is far better for editing the text, but back when people thought Vatican pal Lat 24 was 7th-century, the manuscript seemed like an impossibly exotic object.
Charlemagne either couldn't read or couldn't read very well, although he began at an advanced age to diligently study reading and writing. And, of huge importance to the study of ancient Latin, he threw his huge influence into the advancement of education, and so by the 9th century the Dark Ages are over -- the Middle Ages continue until the Renaissance -- and 9th century manuscripts of the classics far outnumber ones from the 4th and 5th century, and with each century the number of manuscripts made which we know today grows, until the 15th century, and printing.