Caracalla, AE27 of Nikopolis ad Istrum.

AV K M AV ANTWNINOC, laureate, draped, cuirassed bust right.
EVTV-XW ETOIC-KVPIOIC-NIKOPOL-PROC I in five lines within wreath.

Varbanov 2911 (this coin); AMNG -.

This coin is unlisted for Caracalla, though a similar reverse 
legend within a wreath is known for Septimius Severus. Pick, 
in AMNG notes that is a possibly a congratulatory message to 
the emperor on the elevation of his son Caracalla to the rank 
of Augustus. The youthful bust of Caracalla on this coin 
tends to support this theory.

With kind permission of Numismatik Lanz, auction 2003. 
Added Oct. 2011.