Countermark

https://rpc.ashmus.ox.ac.uk/countermark/614 
GIC 489
?, 'Boetian shield', possibly a 'Θ'
circular 
2.5 mm 
 

Coins with this countermark

Number Image TypeNumber CoinNumber VolumeNumber
RPC I, 1335 Show 1335 1 1
RPC I, 1331 Show 1331 2 1
RPC I, 1331 Show 1331 4 1