Joseph Sarkissian "ANT could be antioch but I can't find any similar ones online." It is indeed from Antioch, similar to the example below. http://www.constantinethegreatcoins.com/Rulers/Maximianus/
RI MAXIMIANUS HERCULIUS 286-305 CE antoninianus Antioch 292-295 CE Pre-Reform CONCORDIA MILITVM Jupiter RIC V 621 H-officina 8
I have an Antoninianus similar to the one presented by Alegandron but the mint mark is Z // XXI Does anybody know which officina is Z ? It is also under RIC V 621 as described at http://numismatics.org/ocre/id/ric.5.dio.621 but I have not been able to find any description of the officinae for this type
Z is the 7th officina. You might find this page useful: http://www.forumancientcoins.com/numiswiki/view.asp?key=officina
This coin was probably minted around the time of Diocletian's coinage reform. Although RIC, vol.VI, lists this coin as having its mint mark in the exergue, coins from this series actually have the marks in the lower field, as this example shows. Bronze Pre-Reform Antoninianus Lugdunum mint, A.D. 287 Obv: IMP C VAL MAXIMIANVS P F AVG Rev: HERCVLI PACIFERO - Hercules, holding branch, club and lion's skin Gamma in field RIC 371 20mm, 3.2g.
I like these pre-reform radiates of Maximian. Maximian, AD 286-308 Roman Æ Antoninianus; 3.78 mm, 23.0 mm, 12 h Cyzicus, AD 293-294 Obv: IMP C M A MAXIMIANVS AVG, radiate and draped bust right Rev: CONCORDIA MILITVM•, Emperor standing right, receiving Victory from Jupiter standing left; Г/XII• Refs: RIC 607; Cohen 53; RCV 13115; Roll-Vélez 9. You can read Saul Roll-Vélez's article (AJN Second Series 26 (2014) pp. 223–243) about these issues here.
Maximian, CONCORDIA MILITVM, Emperor standing right, receiving Victory from Jupiter standing left, Cyzicus: CONSERVATOR AVGG, emperor standing facing, head right, holding scepter, facing Hercules, standing facing, head left, resting hand on grounded club, each sacrificing out of patera over lighted table-altar, Siscia: VOT / XX / H within wreath, Rome: VIRTVS AVGG, Hercules standing right, holding trophy, club, and lionskin, Rome:
Just sharing the Antoninianus, 7th officina with a close-up of the reverse; don't know why Victory is hard to see in the "normal" picture, maybe too much light 20mm, 3.75 g Obverse: IMP C M A MAXIMIANVS P F AVG Bust of Maximian, radiate, cuirassed, r. Reverse: CONCORDIA MILITVM (Dedicated to harmony with the soldiers) Maximian, draped, cuirassed, standing r., holding short scepter in right hand and receiving Victory on globe from Jupiter; Jupiter, standing left, holding long scepter; mint mark Z // XXI Syria, Antioch, 293 AD struck under Diocletian Reference: RIC V Diocletian 621