Very Worn But Identifiable?

Not sure we are going to get too far with this one! Looks Roman to me and the reverse looks like one of the Camp Gates ones, with, I think, "AUG" visible around the side, but that is as far as I can get.

The design is a campgate, commonly described as the entrance to a roman camp or town/city, and they were issued for a long time by a lot of emperors. However, the towers flanking the gate tell us it is a later example, and the surviving letters indicate that the legend is SPES ROMANORVM (Hope of the Romans). The star between the towers confirms this. This type was issued by the usurper Magnus Maximus and his son Flavius Victor. Magnus Maximus, while a scarce ruler, is leagues more common than his son, so it is almost certainly one of his.

Magnus Maximus is a rare ruler; he usurped Britain and Gaul from Gratian (who he killed) and successfully negotiated to become the official emperor of the Western Empire, ruling Britain, Gaul, Hispania and Roman North Africa. He pushed his luck, attacking his co-emperor Valentinian II and forcing him from Mediolanum (Milan, sometime capital of the Western Empire), who promptly ran to Theodosius (Emperor of the Eastern Empire) who dispatched the army of the East to depose him. He surrendered and was put to the sword in 388; this marks the end of true imperial presence in Britain and Northern Gaul. The empire would formally abandon Britain in 410.