I'm thinking more of a William III half penny. If so, that's VERY old. The copper "reales" were termed maravedis and most were irregularly shaped. That's a great find. I think with a little mechanical cleaning you'll pull more off of it.
How should I go about cleaning it? edit: I looked up that coin and every one I saw had the letter T to the right of the bust forehead. I am almost certain the letter in that position on my coin is a D. And, I think I see a U at the lower left side of the coin.
I think that obverse legend matches up with what is seen on a France Louis XV copper. Maybe a sol. The weight is right for that, though they are about 25mm - so a bit smaller than a large cent.
First, I would like to apologize for being too lazy to get my calipers out for a definitive measurement. It is 25.11mm. I can't make out much on the back but I think I see some numbers, however they are too faint for me to read.What date range would a Sol fall into?