Constantinus II - campgate (N2206)

CONSTANTINE II (Caesar, 316-337). Follis. Thessalonica.
Obv: CONSTANTINVS IVN NOB C.
Laureate and cuirassed bust right.
Rev: PROVIDENTIA CAESS / SMTSΔ.
Camp gate with two turrets; above, star.
RIC 157.
Condition: almost very fine.
Weight: 2,88g.
Diameter: 19 mm

Over time in the Roman Empire, borders (limes) had become the lines of defense against the barbarians tribes trying to invade the territories. Towers for observation and defence were sometimes built for the protection of the different towns. The only real campgate construction preserved from that period is Porto Negre from the city of Trier in Germany. (Cited from: https://www.cointalk.com/threads/a-simple-campgate-thread.370908/)