RIC 277
Serdica. 

1. Obverse legend-Estiot does not give the short legend AVRELIANVS AVG to
Siscia at all. In RIC, it is listed for only two coins, both ORIENS. The
coins listed there as Siscia are reattributed to Milan in Estiot. This
obverse legend is used with some frequency at Serdica (and other mints),
but not at Siscia.
2. The obverse lettering still looks more like Cyzicus, 
but I
have observed several of my coins that are undoubtedly Serdican that
have some of the same features, especially the open-topped A's.
3. The portrait - a smaller bust, with much larger fields, like
this one, is more typical of Cyzicus, but I have found several
pictures of coins from Serdica with the same feature. 
4. The rx scene-I still think this is too "eastern" in style to come from a
central mint like Siscia; if I had not seen the obverse, and the type
existed from there, I would have said Antioch. Still, Serdica was more
influenced by Greek traditions than Siscia was.
5. The mintmark-Estiot lists this coin with mintmark S from Serdica (Venera
9890-9891). So, the listing in RIC would just be incomplete for this
series (since only P is listed), but that is common. Webb makes the comment
that coins from the mints of Siscia and Serdica are "rare in the
west", which seems odd today, but was apparently true in his time. Of all
the unlisted or variant coins I have from Aurelian through Probus, more
than half of them come from Serdica.

Contributed by Stephen Coulter, Mar 2001