You can find some really good deals on ancient coins with dates, too. I have a bunch from ancient Rome that were dated anywhere from 10 BC to 100 BC, and they cost only a few bucks a piece.
This may be the main reason stamp collecting has seen a big decrease in recent years. Every country around flooded the market with special and commemorative issues. The market was basically overwhelmed and collectors stopped getting excited about all the new issues. To a lesser extent the same happened with coin collecting.
If your ancient Roman coin actually says “10 BC” on it, I’ve got news for you…
Whoosh!
That’s a shame.
I was going to try to sell him the skull of John the Baptist when he was a young boy.
What was the earliest anyone put an A.D. date on a coin? Anno domini wasn’t even calculated until sometime in the 4th century and I’d be surprised if anyone dated coins with them immediately or even for several centuries thereafter. Anyone know what the earliest issue with them was?
Very recently there have been a spate of stories that certain individual British coins and notes just issued, notably the unbelievably foul new plastic £5 note, are worth 100s and 1000s times their face value.
Sadly I have better things to do than check the issue number on every note I touch.
Looks like it was a Danish coin from 1234 AD.
Thirty years ago I sometimes saw prices in rural markets written with Thai numerals, but they’re less common now, appearing mostly on ornamental or official documents. All the numbers and dates on my wife’s identity card are now shown exclusively in Arabic numerals.
One place I’ve seen Thai numerals is at tourist venues with higher prices for foreigners. The pricing information for Thais is all written only in Thai with Thai numerals.
Great minds think alike! 
I clicked on the thread to post this joke, but Earl Snake-Hips Tucker Ninja’ed me.
I used to work with a woman originally from Thailand who had married an American soldier and moved to the US decades ago. I once showed her some Thai coins that I had (from a batch of assorted foreign coins bought by weight on Ebay) and asked her what the dates were on them. She thought I was an idiot to not see what is so clearly stamped on the coins until I reminded her that I couldn’t actually read Thai script…
The point in that thread about dating being tied to assurance of coin quality is key. Then it became a “we’ve always done it this way” thing.
It still happens from time to time. E.g., the US minted silver Kennedy halves in 1964 just as the price of silver made making silver coins a bad idea. They continued to mint coins with “1964” on them well into 1965. Late in 1965 they switched to the silver clad form. But it was December so they continued minting those for quite a while into 1966.
If you have a 1964 half, it might have been minted in 1965. If you have a 1965 half it most likely was minted in 1966. The “date” is about the coin format, not the year.
A dated coin with he Islamic date of AH 17 is known to exist, which would correspond to 638 AD.
From Wiki, "*Though Cook and Crone in Hagarism: The Making of the Islamic World cite a coin from 17 AH, the first surviving attested use of a Hijri calendar date. * Islamic calendar - Wikipedia
Japanese coins still use dates in the year of the reign of the emperor. Here is a conversion source:
Please stop making statements like this that are not well founded.
the coins in the Maghreb use both calendars.
It is also the case in the Jordan etc.
I very much doubt that the dating is anything to do with coin collectors. The proportion of people, even of coin collectors, who would feel the need to collect one coin of each year has to be vanishingly tiny.
As others have said, it’s done for accounting purposes, and because “that’s how it’s always been done”.
It was part of why they delayed minting coins dated 1965 in the USA, though. There was a (false) belief that collectors were causing the shortage of silver coins.
That’s exactly what most coin collectors collect. Not only one coin of each year, but also various mint marks. For example, if I collected Morgan Dollars, I’d collect one Morgan Dollar of every year they were issued, and every mint mark.
If I collected only one Morgan Dollar, and one each of every other type of coin issued, that would be a “Type” collection. Other collectors are only interested in one particular denomination or perhaps one particular year.
And really hope to stumble across some ccs.
Coin collectors do tend to collect coins for each year … and Whitman Publishing makes some albums for just that case …
Perhaps you mean coin investors … folks who buy rare and precious coins in the hopes they will increase in value and then sell them … they focus on specific coins and dates …
The evil and dangerous numismatic lobby is out there … undermining our economy one penny at a time …