The dating formula on this coin — ANN CCLVIII, "year 258" — refers to Sinope's colonial era, counted from the city's refoundation as a Roman colony under Julius Caesar in 47 BC. That local reckoning places the strike squarely in 211–212 AD, coinciding almost exactly with Caracalla's murder of his brother Geta and the subsequent damnatio memoriae that erased Geta from monuments, inscriptions, and coinage across the empire. Provincial mints like Sinope continued issuing under the sole reign without interruption.
The dating formula on this coin — ANN CCLVIII, "year 258" — refers to Sinope's colonial era, counted from the city's refoundation as a Roman colony under Julius Caesar in 47 BC. That local reckoning places the strike squarely in 211–212 AD, coinciding almost exactly with Caracalla's murder of his brother Geta and the subsequent damnatio memoriae that erased Geta from monuments, inscriptions, and coinage across the empire. Provincial mints like Sinope continued issuing under the sole reign without interruption.