I'm pretty sure I have attributed this coin correctly as being of Severus Alexander. I note, however, that the sigma used on the obverse inscription is not lunate (i.e., not like C), but very block-like. I am aware that a C is sometimes engraved like an E but without the middle line, but this looks more like a capital T with another cross bar at the bottom. Have you seen sigmas written in this way? And, as usual, you are invited to post your Severus Alexanders, coins of Nicaea, coins with weird sigmas, and so on -- whatever you think is relevant. Severus Alexander, AD 222-235 Bithynia, Nicaea 4.57 gm; 21.5 mm Obv: Μ ΑVΡ CΕV ΑΛΕΞΑΝΔΡΟC ΑV, radiate and draped bust, r., seen from behind. Rev: ΝΙΚΑΙΕΩΝ between three standards. SNG von Aulock 634; SNG Copenhagen 520 var; Sear 3287 var. (laureate bust). Detail of MΑVΡCE from the obverse inscription at the 8:00 - 10:00 position: Detail of the ΔΡΟCA from the obverse inscription at the 3:00 - 4:00 position: