Hello everybody. This is my first post, so I hope this is the right place in the forum for the topic. So, the reason for my post is that I stumbled upon an old coin. I tried to find more information about it, and it turned out to be from the Roman Empire. It is 20 mm in diameter and weights around 3.6 grams. By trying to understand what it is written on it and some pictures from the Internet, I managed to find that it is from emperor Constantine The Great. Since I would be happy to know more about it, I would be grateful of you could advise me how exactly to do that. I compared it with some photographs I found, but there are differences. Also it turned out that taking pictures of coins is quite tricky, so I apologize for the quality.