Paphlagonia. Sinope, (3rd century BC) AR Drachm (21mm, 6.01g. 12h). Female head with mural crown to the left, c/m: frontal head of Helios with ΣINΩΠEΩN between the rays. R/ ΣI-NΩ, Poseidon enthroned to the left with a trident in his left hand, monogram in the field to the right, the counterstamp is embossed as a raised head of Zeus. Rec.gén I 1 192.47 pl. 25.33; SNG BM 1515ff. (Var., but with the same counterstamp). Beautiful toning, Very Rare. Good VF
The unusual counterstamp probably dates from the time of the alliance between Sinope and Rhodes