the coin below has an unofficial campgate overstruck on an IOVI with one of the Caesars on the obverse.
There have been a few topics on overstrikes of the IOVI coins, so I will just quote some from another post.
"The IOVI coin was struck from A.D. 321- 324 and had half as much value as coins being struck in Constantinian mints and of course after the defeat of Licinius in A.D. 324, these coin would have been demonetized completely. Arles began striking VIRTVS campgates in A.D. 325; so this coin could have been overstruck pretty shortly after it was originally struck.
An interesting coin which tells the story of the conflict between Licinius and Constantine, with Constantine coming out on top...literally!"