Today's Mystery Coin is about as ugly as they get. The top view is the reverse. The bottom view is the "heads" or obverse. It looks so flat and clean that it almost appears to have had the Emperor/King/Shah scraped off in a purposeful defacement. But what I found initially fascinating about this coin was the hole near the top.
Ancient coins often turn up with holes in them. In fact I have another one in better shape:
This is a common low value coin from one of Constantine's squabbling descendants. A rather inexpertly drilled hole near the top looks like where you would place a loop, so that this could be worn as a pendant.
When researching the question of ancient coins with holes in them I ran across this very thoughtful discussion that also has some photo galleries that put my examples to shame holed ancient coins.
But getting back to the coin of the day, note that it is not a nicely drilled/punched hole as in my second example. Zooming in closer...
This has been crudely punched through with a knife blade or something akin to it. There is corrosion on the edges so this is not recent damage from being excavated clumsily. The hole was made in such a fashion that the side with lettering was preserved, so we have to assume that it was of greater importance to whoever was altering this coin for display purposes.
This is one of those coins that is really too far gone to identify. My best guess is that it is something like this:
Moonmoth coins site. It shows a bronze "follis" coin from a Byzantine Emperor. These are just about the only ancients that have this odd reverse showing multiple lines of text. This example is from Leo VI circa 900AD.
My example is similar in style but clearly a different Emperor. By playing with magnification and squinting I "think" I can make out just a few letters...
At this point a responsible historian would just say, "who knows?". But a frivolous sort such as I can imagine that the coin actually says:
So there you have it, all you need is a plausible mint transposition of the I and R to give us a nonsensical identification of a coin from King Arthur!
Oh, and if anyone has an actual sane identification I would love to hear from you.