Ancients That Were Never "Lost"

yes, an interesting question indeed. What would even constitute proof? The trail of most things ran cold from the fall of the "western" roman empire until the middle ages. If the trail of the line of kings ran out, then what chance does the trail of a small item like a coin to be preserved?

Perhaps there would be better odds of finding such a trail via the Byzantine empire.

No. Every single ancient coin in collections today was dug up out of the ground sometime in the last 1000 years. You have to remember, Dark Age Europe was not a time when people cared about the finer things in life. Even the kings during the Dark Ages would have seen an ancient Roman coin as just another piece of bullion. There is a record of a vast hoard of Roman silver coins found in the territory of a mediaeval Italian prince. The prince had the whole hoard melted down.

While there are ancient records of certain people "collecting coins" (such as the mention of the antquarianism of Augustus in Suetonius) and there is strong but indirect evidence that some kind of "Imperial coin collection" must have existed during the Roman Imperial period which celators could access and copy, none of these ancient coin collections have survived intact as collections and no individual coin has a provenance which can be traced back to such a collection. Coin collecting in the modern sense began during the Renaissance, particularly when it was given a positive review by Petrarch as being something which any prince interested in history should be involved with. The oldest coin collections in the world date to this time (around the 1300s), including the Vatican collection (assembled by various mediaeval Popes) and the collections of several royal houses (some of which now belong to their respective national governments).

Some coin hoards have been discovered that show clear signs of being more than simple random accumulations of coins from circulation, which indicate that that particular hoard might have been somebody's "coin collection". But these, too, have had to be dug up, with no clear chain of ownership and certainly no preserved knowledge of whoever it was that originally assembled the collection.

Now, the history of coin collecting is older and stronger in China; there may be some collections older than 1000 years over there. I'm not familiar enough with the scene there to comment. But in the West, the Dark Ages were simply too long and too dark to allow for such a luxury.

That just means that someone found a big enough hoard to be worth using it as circulating money, during a shortage of regular circulating money.
A Roman coin actually circulating for anywhere near as long would have been worn unrecognizably smooth (I'm not aware of any examples of coins circulating continuously for more than 250 years or so, and the 250-year ones are circles of metal with only the barest hint of design; of course it would have been quite hard to identify any that circulated longer).

It is vaguely similar to the well-documented example of late 1st century Roman coins being reused in the 5th century (by some Germanic tribe, can't recall which one).

I would think that a few coins would've wound up in some church or something prior to the 1000s and been held by them for one reason or another until now, but I've never been able to find an example of it.

A lot of them weren't "lost" in the sense that someone dropped it but they buried with the intention of recovery. There were no banks as we understand them and with wars and general upheavals it was really the safest thing to do.

Sap- Wow! that is amazing! What is your source on this? Has there been scholarly or other literature published on this? I would love to read it.

Athalbert- Do you have any picture of such coins? I've seen counterstruck maravedis coins, but never Ancient Romans struck with a denomination in maradevis.