That's a great-looking coin chrsmat.. the patina really makes it pop. As per Doug's suggestion: In 311 Galerius got a bad disease that made his groin parts swell up. Worms started to eat him and his body started to rot, so much so that some of his doctors couldn't handle the smell. The weak-stomached doctors were executed right away, and the rest of them were executed when they couldn't figure out how to stop Galerius from dying horribly. It was while he was thus falling apart that Galerius decided to stop the persecution of Christians. Maybe he thought his illness was a message from the Christian god? Maybe the disease hurt and he just decided it was mean to make other people hurt?
Galerius's condition was totally natural and did not require any divine wrath. I think you may like this article. http://www.researchgate.net/profile...sableCoverPage=true&origin=publication_detail