Here is a nice example of this rarer type. Though it was included in RIC VIII and dated to A.D. 348, it must have been issued in A.D. 330 for the inauguration of Constantinople. There is a similar companion piece with CONSTANTINOPOLIS obverse and Pax reverse.
ROMA Constantinopolis Commemorative
A.D. 330
17mm 1.8gm
OBV: ROMA- helmeted and draped bust of ROMA right.
REV: Anepigraphic- Virtus, helmeted and in military dress, standing left, head right, holding spear in right hand and resting left hand on shield. P-R across fields.
RIC VIII Rome 104
For more on these anonymous coins, an earlier post-
http://www.lateromanbronzecoinforum.com/index.php/topic,859.msg2508.html#msg2508
