Doesn't appear to be many types struck at the Sirmian mint for Constantine. Arrived this morning, CONSTANTINE I. Æ. Follis. Sirmian 324-325 AD Obverse: CONSTANTINVS AVG. Laureate head right. Reverse: SARMATIA DEVICTA. Victory holding trophy and palm, stepping over a Sarmatian captive. 2.99g. 20mm RIC VII, 48
Nice detail. From Trier CONSTANTINE I AE Follis OBVERSE: CONSTANTINVS AVG, laureate head right REVERSE: SARMATIA DEVICTA, Victory advancing right, holding trophy on right arm, branch in left hand, spurning captive seated on ground right, head turned back, STR(cresent) in ex Struck at Trier, workshop S, 323-4 AD 2.8g, 19.4mm RIC 435
Excellent reverse! I do not have that type but I will share a few coins of Constantine.. Struck A.D. 319 19mm, 3.32gr IMP CONSTAN-TINVS AVG -- high crested helmet, cuir., spear across r. shoulder, shield on left arm VICT• LAETAE PRINC PERP -- two Victories stg., facing one another, together holding shield inscribed VOT PR on altar inscribed with I In ex. •ASIS• Siscia Mint Obv: CONSTANTINVS AVG, laureate head right. Rev: D N CONSTANTINI MAX AVG, VOT XX within wreath Mintmark: Epsilon SIS sunburst RIC VII Siscia, Below is my favorite coin a Constantine.. a large follis (29mm) and struck as Caesar. Constantine I (Caesar, 306-309). Æ Follis (29mm, 8.59g, 12h). Heraclea, 306-7. Laureate head r. R/ Genius standing l., holding patera and cornucopiae; HTB. RIC VI 31
The SARMATIA type was issued from five mints-- London, Lyon, Trier, Arles and Sirmium. Here are the other three mints not already shown. London Lyon Arles
As I have a sub-collection of Roman Captives coins, I like this type. Some nice examples here. I'm still a little mad at myself for not getting one particular PLON example recently at CNG. But my favorite example of this reverse is also from Sirmium, just like the OP coin: Now that you mention it, though, there don't seem to be many other bronzes types for Constantine from this mint. I do have some Constantius II "fallen horsemen" from Sirmium, though! This one's not so nice, but with an interesting control symbol "A" beneath the horse (RIC VIII 40 or 44?):
