Constantine I AE Follis. AD 306-337. Siscia.

Obv: CONSTAN-TINVS AVG, laureate head right
Rev: PROVIDEN-TIAE AVGG, Campgate, eight layers with dots
in top layer, two turrets, no doors, star above.

Mintmark dot Gamma SIS dot.
RIC VII Siscia 200, rated C3.

ebay sale, Feb. 2011, seller: Pannonii, Slovenia.