Countermark

https://rpc.ashmus.ox.ac.uk/countermark/854 
GIC 730
square(?) 
c. 5 mm 
The style of the punch is close to that if GIC 729 and 731, but does not certainly belong in either group.date agrees well with GIC 735, but the punch is too large to be attributed to that group 

Coins with this countermark

Number Image TypeNumber CoinNumber VolumeNumber
RPC II, 2279 Show 2279 8 2