Countermark

https://rpc.ashmus.ox.ac.uk/countermark/237 
GIC 111 iv
laureate bust r. (on obverse)
circular 
6 mm 
Antioch (Syria)
possibly applied at Antioch (Syria). Head might represent Caligula, under whom no bronze coins were struck at Antioch. 
List of countermarks View on a map

Coins with this countermark

Number Image TypeNumber CoinNumber VolumeNumber
Show 224
RPC I, 4247a Show 4247 2 1
RPC I, 3868 Show 3868 36 1