Countermark

https://rpc.ashmus.ox.ac.uk/countermark/952 
GIC 838
CL·CAES (on silver coins)
rectangular 
12 x 3 mm 
the cmk may have been connected with the annexation of Thrace as a province under claudius 

Coins with this countermark

Number Image TypeNumber CoinNumber VolumeNumber
RPC I, 1782 Show 1782 1 1