very interesting field indeed, there are so many interesting denominations.
I believe they first started to put dates on coins in Europe in 15th/16th century. It means well before they started to use machines to struck coins.
German states especially minted tons of various coins
I've just checked what first came in my hand, grabbed an album and here I'm looking now at a silver "1 marck danske" from 1563, silver 30 kopeks/2 zlote 1837, some polish coins etc. I have had many such weird denominations like 9 cavalli and what not, still have probably, I need to check it more thoroughly
Yes, I agree. My oldest coin with a date from our calendar is from 1474, 1 stuiver from Groningen. Date given in roman numerals. My oldest with arabic numbers is from 1500, a double vuurijzer from Brabant. Of course, these two are not much to look at. Still, the numbers (letters) are clearly visible, which I regard as a must. I know the French minted coins such as 33 sol and 44 sol but they don't actually have "33" or "44" on them, leaving me less interested.
I have the 9 cavalli. That is my only 9 given in arabic numbers. I also have a 12 florins 9 sols from Geneva, but that one again is written XII and IX. The 30 kopeks/2 zlote I do not have. I don't have any of the Russian/Polish double denominations. Have been looking for those, actually.