I received this coin in a lot of other, mostly medieval coins. I don't collect very many Roman coins and I'm not good at attributing them but I believe the coin is a silver Denarius issued in 123 BC under C. Porcius Cato. RRC 274 1. I'd appreciate any input or corrections for this attribution!
It looks good to me but I don't know these older Roman coins well at all: http://www.wildwinds.com/coins/sear5/s0149.html