According to historians, monks saved many of the ancient books and documents from antiquity. In essence, a monk in a monastery copy room would copy a Roman /Greek manuscript. In time, the old copy would fade and rot away, so there would be a considerable need to re-copy these, every few centuries. My question; how many copies would have been made, say from AD 500 until AD 1600? And, did the copiers introduce errors in the texts?
Reported.
Moderator Note
Since this had nothing at all to do with the topic that it was posted in, I am assuming that this was intended to be a new thread and have split it off as such. If this was meant to go somewhere else, please let me know.
That seems harsh? 
Bart Ehrman’s Misquoting Jesus is a full book about the copying and translating of books of the Bible over centuries and the errors and interpolations that were introduced. The Bible is at an extreme of the curve, of course; other books were copied less frequently or hardly at all.
No meaningful answer can be given about numbers. Scribes and the elements of texts - ink, parchment, vellum, paper, desks, time - were either luxury items or religious devotion. The amount of resources that could be devoted varied from time to time and place to place constantly. A place might have a battalion of scribes at work at one time and then see its numbers dwindle to near nothing a century later.
Most copying was done to pass the books on to other outposts of literacy. Some may have been done to replace a worn original but it was more likely that a copy would be made from a copy because the original had been destroyed by fire or flood or war or other disaster.
[QUOTE=engineer_comp_geek]
Since this had nothing at all to do with the topic that it was posted in, I am assuming that this was intended to be a new thread and have split it off as such. If this was meant to go somewhere else, please let me know.
[/QUOTE]
WTF?
To the OP.
Documents were copied as many times as needed, (the Egyptians, Persians and Romans had literally Armies of scribes), and copies sent where they were required, say a report from the port master in Hegra (modern NW S Arabia) might see multiple copies sent to Petra (the provincial capital) and they might make further copies to send to Rome if needed.
Important manuscripts were typically like our books, had multiple copies made in multiple places.
For works of private persons, like Pliny or Ceaser, or Avicenna, they would usually get a scribe to make a copy to give to friends, who might give copy to their friends and eventually if the work is recognised, well many people might make copies.
I thought the questioner was asking how many times a piece of vellum ( or paper etc. ) could be scrubbed and rewritten on as a palimpsest.
And no idea myself.
What’s harsh or WTF about this thread? It’s not like the OP got a warning for accidentally posting in the wrong window, or something. The moderators fixed a minor mistake, no big deal.
IIRC, there are multiple copies all over the medieval world - so we have a pretty good idea what the originals were. Based on the numbers of different works, the errors appear to have been minimal. From what we know, the copyists did not typically try to reword things as they copied - they did verbatim copies, so only spelling mistakes and occasional missed bits might be the issue.
Of more concern to historians, are the deliberate rewording; in Josephus, for example, someone most likely added wording to enhance the passing reference to Jesus. But, since Mary’s virginity was not an issue in the early church, references to Jesus’ brothers were not edited out early on, so these anomalies survive. This would be the issue - embellishment and censorship to reflect orthodox viewpoints.
I don’t think deterioration was the major factor in the number of times a work was copied. The biggest determinant was how popular the book was. A popular text might be copied out every year while an unpopular text might sit on the shelf uncopied for a century.
Moderator Note
I wasn’t trying to be harsh, and I apologize if it came across that way.
This was originally posted to the Senator Clinton thread, which it obviously had nothing to do with. It looked to me like just an honest mistake on the OP’s part, especially since it contained a new title (which I used as the title for this thread). It seemed obvious that the OP intended it as a new thread. No biggie.
There’s no warning and the mod note is only to let everyone know what happened, for the benefit of those that saw it in the other thread or were wondering why the thread was reported. Other than posting to the wrong window, the OP didn’t do anything wrong. The OP isn’t being punished in any way. It was just an honest mistake.
The most well known mistake in the Bible was the substitution of “celibate” for “celebrate”. 
“Reported,” without a qualifier such as “…for forum change” is usually only when a Bad Post is posted, said post being subject to instant opprobrium.
“Reporter” or mod didn’t pre-empt such heinous accusations. No biggie.
ABTM picks up on this.
I’m also a fan of “I said I hate ‘figs’.” (OMFG you guys, I said I hate "FIGS" - Facepalm Jesus - Meme Generator)
What I was getting at was the longevity of medieval inks, vellum, etc. Take a famous text (like Caesar’s “Gallic Wars”). If you had a copy from AD 300, would such copy last 600 years? Or would it have to be re-copied every two centuries or so? Were there lots of monks doing the copying, or was this actually a pretty uncommon activity?
I dunno if it was a case of “this text is getting pretty worn, time for text 2.0”.
Rather, pre-printing-press, copying was the only way to make a new version. So more like “That new Monestary over there wants copies of these texts, they will trade us for copies of these other texts, let’s get copying”. Or some aristocrat wanted to beef up his library with the Gallic Wars. They had to pay someone to copy it out by hand, of course.
The issue was more multiplication of copies versus destruction of copies - in wars, fires, other accidents.
If left dry and otherwise protected, there is no reason texts on vellum can’t last forever - hell, we have several texts of extreme antiquity, they are just fine today. Book of Kells dates from 800 or so.
The problem is not so much the text wearing out, as the books being used at toilet-paper by Vikings, etc.
I’d say it was uncommon. Old texts were incredibly rare and valuable. They would be protected as much as possible. As Malthus says, vellum is not paper. We have any number of perfectly readable ancient texts today. Recopying one every two centuries is unlikely to have been necessary. That doesn’t mean it never happened, but it was never a regular, recurring event as you suggest.
We do have thousand-year old books and documents. For things like Egyptian papyrus we have documents several thousand years old.
A lot depends on the storage conditions. Dry, protected environments meant parchment/vellum/bamboo (in Aisa)/whatever could last a long, long time, millennia even. Damp environments, more grubby fingers paging through a document, and so forth meant less longevity. Insect infestations, fire, careless handling could all destroy a document.
In the old days, though, books were incredibly valuable. They were protected more often than not, with some exceptions due to barbarian invasion or religious crap.
There were book publishers in the Roman Empire, you know. The television adaptation of Robert Graves’ I, Claudius depicted them. You can read about them here:
Of course, “publishing” meant that multiple copies were written out by hand, but it was common enough to be a commercial enterprise. It is possible that books were copied from a dictated original, read to a roomful of copyists. The same procedure appears to have taken place in the Medieval world, since some errors in texts appear to be phonetic errors, rather than textual copying errors.
There are also multiple copies of several works from the classical world besides religious works. We have multiple copies of the Iliad, the Odyssey, ad other mythological works.
There are over a dozen manuscripts of Caesar’s De Bello Gallico, although all are from about a thousand years later. Here are twelve of them listed (although the page admits there are others):