Constantine I The Great AE3. Siscia Mint 328-329 AD. 
Obverse: CONSTAN-TINVS AVG, laureate head right. 

Reverse: PROVIDEN-TIAE AVGG, camp-gate with no doors and two turrets, star above; BSIS(two crescents) in exergue. RIC VII: 214. Size: 19mm.

Numismatic Notes: VF overall and more appealing in hand! Splendid green and brown patina! An intricate and well struck city gate reverse!