Constantine I IOVI from Siscia overstruck with unofficial VLPP

Constantine I. AD 307/310-337. Æ Follis (21.5mm, 4.06 g). Contemporary imitation. Struck circa AD 320s. Helmeted and cuirassed bust right / Two Victories standing vis-à-vis, holding inscribed shield on altar. Overstruck on an a Siscia mint follis of Constantine I. Sergeev 232-7. For undertype cf. RIC VII Siscia 7

IMP CONSTANTINVS AVG; laureate head right.
IOVI CON-SERVATORI; Jupiter standing l., chlamys across l. shoulder, leaning on sceptre and holding Victory on globe in r. hand; eagle with wreath to l. on ground; in right field ?.
in ex. SIS


This IOVI CONSERVATORI was issued A.D. 313- 315. This type was demonetized after the monetary reform in A.D. 318, which introduced the VLPP in bronze. Normally, the unofficial VLPP are circa 17-18mm, close to the official issue; but this coin, struck on an IOVI flan is almost 22mm. So, because of the size and crude overstrike, everyone would have known what it was, but it must have been more important to at least attempt an overstrike, rather than continue to circulate an unaltered IOVI.