I can make out "TANTINVS" on the face. May be "CONSTANTINVS", which fits with your guess about a Roman connection. Narrowing search through Numista catalog for 19 mm Roman coins with CONSTANTINVS, I don't see any exact matches.
I hope this helps a little! Good luck with the puzzle!
It is indeed a follis of Constantine I.
Obv. : IMP CONSTANTINVS AVG, helmeted laureate and cuirassed bust right.
Rev. : VICTORIAE LAETAE PRINC PERP // VOT PR
Can't read the mintmark below.
Статус изменён на Решено(thecabinetguy, 23 Янв 2019, 02:07)
