I have 2 old 10 Centesimis from Italy. one is from 1863 and the other is from 1866. I was just looking at them out of bordem, and then I noticed something. On the back of the 1866, I noticed the letters OM. I dont know what it is, so I looked on the 1863, and there is nothing in that spot. So I think its a mint mark or something. Can somebody help me?

I am assuming either they are mintmarks or actually the initials of mintmasters who worked on the dies. Well, that's for Russian coins, but I don't know much about Italian coins...

If it were initals wouldnt it be on the other one too?

The "R" is for Rome, which has a mint. Since 1861, 7 mints have become inactive in Italy.

Its not an R. I looked it up, and found a pic to clarify, here is a link: http://www.lemonete.com/index/catalogo/Vit...0_centesimi.htm

Sorry, don't know why I went with the R. Anyway, M is Milan

Its not just an M, its OM.

Ok!! I was given this info on these coins from another forum:

"OM" is the mintmark for the Strassbourg Mint. According to the Standard Catalog of World Coins the copper 10 centesimi (KM#11.5) was minted there in 1966-1867, and is valued at $1.50 F to $55 Unc. for both years in the 2002 3rd Ed.

It was produced in Paris without a mint mark (KM#111.2) in 1862-63 and 1866. The early ones are listed at the same values as the Strassbourg coins.

Between 1862 and 1867 the coin was produced at Heaton in England, as well as at Italian mints in Milan, Naples and Turin. With all that activity, there was a total mintage of only about 350,000 pieces.

Correction:
The 1863 10 centesimi from the Paris mint (without mintmark) had a mintage of 80 million and is KM-11.2.
The 1866 Strasbourg (OM) had a mintage of 20 million and is KM-11.5.

Lol, I was just about to post that from the other forum.