Actually I am very much an amateur when it comes to most ancients. The coin is Roman, but not an "early" Roman. It is an imperial issue probably between 200-400 AD. Hang on for a bit and I am sure someone here knows EXACTLY what you have.
I'm having more trouble than usual in making out the legend, it might be blundered or a barbarous copy of a radiate coin.
http://www.constantinethegreatcoins.com/barb2/ should help explain what they are. It's a site maintained by @Victor_Clark . Though I suppose yours is a 3rd century imitation.
Huh interesting. That’s still awesome that it’s that old! What made you think it was a counterfeit? And wow it sure is a good one!
How do I know? Here is an example The top one is an official issue, bottom is an imitation. The official issue has readable inscriptions where as the imitation is some garbled non-sense. You can also tell from the style of each. Though the imitation may look alright it does look cartoonish compared to the other. Yours is also based on some official issue.
I'm rather sure the coin is a Provincial of Gallienus. The city and reverse will take longer. It rather reminds me of the Iconium with Marsyas I bought in a JA auction not long ago but the reverse is different. I see no reason to doubt it is ancient and official despite the popular vote to the contrary.
From his camera It's his coin. RIC is for Roman Imperial coins, so Provincials are generally not found there. You'll have to dig through various online databases, public domain books, and archives. ... I agree with Doug about it being a provincial issue of Gallienus. Sometimes they have Latin letter instead of Greek, so maybe that was throwing people off. The obverse legend is consistent with Gallienus.
RIC is a book series Roman Imperial Coins. There is a series in progress for Provincial coins but not all the volumes have even been begun. Gallienus Provincials will be a big job. Is Fifty years reasonable? There are many references that I do not know and very few online. Compare your coin to the ones shown here: http://www.wildwinds.com/coins/greece/lycaonia/iconium/t.html I remain less than certain of the city. Feel free to research. ID of ancient coins is not always an obvious thing especially when legends and details are weak.