Huh! That's pretty bizarre. There's no way a coin in such good condition has been in circulation 150 years, they wear out faster than that. It must have spent many years in a piggy bank or something.
Ah, yes, thanks!
Marcus Aurelius would have been my second guess (after Antoninus Pius). Problem being that both are normally shown with a beard. So I'll guess this is from the time before he became emperor (161), in which case 150 was maybe not a bad guess. Good enough for me!
These things have been studied to death. I'm sure some scholar somewhere has already assigned this coin to a specific mint and a narrow timeframe, pretty much like any Fuji, Trek, Schwinn, whatever.
If you want to know more about the guy, his "Meditations" is worth reading. Not a page turner by any means, but full of wisdom.
Thank you for your observations on this. I’d settle for 150AD! Fascinating.