Severus II AR Argenteus. Serdica, AD 305-306. 3.59 g.

SEVERVS NOB C, laureate head right.
VIRTVS MILITVM, campgate, seven layers, three beacons, no doors.

Mintmark dot SM dot SDB dot. 

RIC VI Serdica 11c (missing); RIC VI Serdica 21 var (Severus as Augustus); Gautier 24 var. (officina). Should be RIC 11c.
Very rare.

With permission of Numismatica Ars Classica, October 2014.