I recently came across this ancient coin that has a rather interesting story. It was sold as a 21mm bronze coin of the Silandos mint in Lydia (Turkey), an autonomous issue under Roman rule most often dated to around the Severan period in literature. Having searched through a number of references I was unable to place the type with helmeted Roma on the obverse and Tyche holding a rudder and cornucopia on the reverse. The obverse is known, for example, on SNG Copenhagen 547.
SNG Cop 547
I then took a closer look at the legend on the reverse, reading EΠI Λ MAPOC Y IE TABAΛEѠ[N ], a reverse type of Tabala in Lydia, not Silandos! Although the reverse legend is known, for example on the coinage of the city under Commodus and Crispina (eg SNG von Aulock 8272), the Tyche reverse design is not recorded for Tabala in the references I have consulted.
There is the thought that such mixes of types of different cities occurs because coining was a specialist craft and one location was contracted to produce types for a number of neighbouring cities. Thus errors could occur with the mixing of city types, although this combination was unknown to Konrad Kraft in his work Kaiserzeitliche Münzprägung in Kleinasien. This looks to have occurred here but, unusually, mixing a known obverse/portrait side from Silandos with a new, unrecorded reverse type from Tabala and is probably unique.
This coin can be bought HERE.