Silver Denarius of Domitian AD 81-96, emperor facing right on obverse and helmet on altar on the reverse. Probably minted in Rome.
Sadly a segment is missing from the coin due to impact damage whilst in the soil over the centuries.
Interesting that the obverse legend Obverse shows DIVI F DOMITIANVS and is read from the outside of the coin anticlockwise. The full description would be CAESAR DIVI F DOMITIANVS followed by COS III or similar.