Constantine I. A.D. 307/10-337. Silvered AE3 (19.41 mm, 3.17 g, 12 h). Siscia mint, struck A.D. 321-4. CONSTANTINVS AVG, laureate head right / D N CONSTANTINI MAX AVG, legend around laurel-wreath containing vota inscription in two lines; Γ SIS radiate semicircle in exergue. RIC I80; C 130; SRCV 16220. EF, silvering very nearly complete.
The "dot" in the middle of the reverse is an artifact of the die-engraving process, a centering-point for the layout. It is not a deliberate part of the device.