1. https://www.acsearch.info/search.html?id=51887 CGB.fr http://www.cgbfr.com/ Description: DIOCLETIEN (20/11/284-1/05/305). Caius Aurelius Valerius Diocletianus Auguste (20/11/284-1/05/305). Aurelianus 286-290 N° brm_136296. Date: 286-290. Nom de l'atelier: Antioche. Métal: billon. Diamètre: 21mm. Axe des coins: 12h. Poids: 3,73g. Degré de rareté: R1. Etat de conservation: TTB+. Commentaires sur l'état de conservation: Beau portrait légèrement stylisé. Revers bien venu à la frappe. Patine vert noir. Prix: 75,00€ N° dans les ouvrages de référence: RIC.323 - C.146. Titulature avers: IMP C C VAL DIOCLETIANVS P F AVG. Description avers: Buste radié, drapé et cuirassé de Dioclétien à droite, vu de trois quarts en avant (A). Traduction avers: 'Imperator Cوsar Caius Valerius Diocletianus Pius Felix Augustus' (L'empereur césar Caius Valère Dioclétien pieux et heureux auguste). Titulature revers: IOVI ET HERCV CONSER AVGG/ (croissant)/E// XXI. Description revers: Jupiter et Hercule debout face à face. Jupiter est debout à gauche, tourné à droite, tenant un globe et un sceptre, recevant un globe nicéphore d'Hercule, debout à gauche, tenant la massue et la léonté. Traduction revers: “Iovi et Herculi Conservatori Augustorum”, (A Jupiter et Hercule conservateurs des augustes). Historique: Dioclétien, né en 245 en Dalmatie (Split), est un empereur illyrien. Il revêt la pourpre après avoir éliminé Aper, préfet du prétoire, beau-père et assassin de Numérien, le 20 novembre 284. Luttant d'abord contre Carin, dernier fils de Carus, il est battu au Margus l'année suivante ; mais Carin est assassiné et Dioclétien reste seul auguste. Il nomme Maximien, un compatriote, césar en novembre 285, puis auguste le 1er avril 286. Il vient de créer un nouveau régime politique, la dyarchie où deux empereurs se partagent le pouvoir militaire et politique, mais Maximien reste subordonné à Dioclétien. Dioclétien se place sous la protection jovienne (de Jupiter) tandis que Maximien est d'essence herculéenne (d'Hercule). Dioclétien passe les dix premières années de son règne à guerroyer en Orient, tandis que Maximien reste en Occident. Dioclétien est le premier empereur du Bas Empire, selon l'expression de Gibbons, et l'instaurateur du dominat.
2. https://www.acsearch.info/search.html?id=62147 CGB.fr http://www.cgbfr.com/ Description: DIOCLETIEN (20/11/284-1/05/305). Caius Aurelius Valerius Diocletianus Auguste (20/11/284-1/05/305). Aurelianus 286-287 N° brm_182400. Date: 286-287. Nom de l'atelier: Antioche. Métal: billon. Diamètre: 22mm. Axe des coins: 12h. Poids: 3,14g. Degré de rareté: R1. Etat de conservation: TTB. Commentaires sur l'état de conservation: Exemplaire bien centré. Beau portrait. Revers de frappe molle. Patine gris noir avec des reflets métalliques, granuleuse. Prix: 45,00€ N° dans les ouvrages de référence: C.146 - RIC.323. Titulature avers: IMP C C VAL DIOCLETIANVS P F AVG. Description avers: Buste radié, drapé et cuirassé de Dioclétien à droite, vu de trois quarts en avant (A). Traduction avers: 'Imperator Cوsar Caius Valerius Diocletianus Pius Felix Augustus' (L'empereur césar Caius Valère Dioclétien pieux et heureux auguste). Titulature revers: IOVI ET HERCV CONSER AVGG/ */Z// XXI. Description revers: Jupiter et Hercule debout face à face. Jupiter est debout à gauche, tourné à droite, tenant un globe et un sceptre, recevant un globe nicéphore d'Hercule, debout à gauche, tenant la massue et la léonté. Traduction revers: “Iovi et Herculi Cosneratores Augustorum”, (A Jupiter et Hercule conservateurs des augustes). Commentaire à propos de cet exemplaire: Poids léger. Avec des restes d’argenture superficielle. Pas de rubans visibles et ptérygezs invisibles sous le paludamentum.
3. https://www.acsearch.info/search.html?id=57090 CGB.fr http://www.cgbfr.com/ Description: DIOCLETIEN  (20/11/284-1/05/305) Caius Aurelius Valerius Diocletianus Auguste (20/11/284-1/05/305). Aurelianus 285 N° brm_158008. Date: 285. Nom de l'atelier: Antioche. Métal: billon. Diamètre: 24mm. Axe des coins: 12h. Poids: 3,98g. Degré de rareté: R1. Etat de conservation: TTB+. Commentaires sur l'état de conservation: Exemplaire sur un flan exceptionnel pour ce monnayage. Très beau revers. Patine grise.    Prix: 75,00€ N° dans les ouvrages de référence: C.146 - RIC.323. Titulature avers: IMP C C VAL DIOCLETIANVS P F AVG. Description avers: Buste radié, drapé et cuirassé de Dioclétien à droite, vu de trois quarts en avant (A). Traduction avers: “Imperator Cوsar Caius Valerius Diocletianus Pius Felix Augustus”, (L’empereur césar Caius Valère Dioclétien pieux et heureux auguste). Titulature revers: IOV ET HERCV CONSER AVGG/ (epsilon)// XXI. Description revers: Jupiter et Hercule debout face à face ; Jupiter est debout à gauche, tourné à droite, tenant un globe et un sceptre, recevant un globe nicéphore d’Hercule, debout à gauche, tenant la massue et la léonté. Traduction revers: “Iovi et Herculi Conservatori Augustorum”, (A Jupiter et Hercule conservateurs des augustes). Commentaire à propos de cet exemplaire: Avec une grande partie de son argenture.
   

Best regards.
Giulio De Florio

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Notes:

(1) I collect in the table the physical characteristics of the antoniniani of the type of figure present in the links above:

Riferimenti	Peso (g.)	Asse di conio (ore)	Diametro (mm)
Link1	3,73	12	21
Link2	3,14	12	22
Link3	3,98	12	24
Link4	3,01	6	18,5
Link5	4,27	-	22

Since there is no information about the physical characteristics of the sample under examination (weight, diameter, coin axis, reaction to the magnet), it will not be possible to carry out a comparative examination with the authentic coins of the period.
(2) The mint of Antioch in Syria worked at the time with 9 officinae, marked with Greek numbers A, B, Γ, Δ, ε, ς, Z, H, Θ.
(3) IMP C C VAL DIOCLETIANVS P F AVG (IMPerator Caesar Caius VALerivs DIOCLETIANVS Pius Felix AVGvstvs). Acclaimed emperor on November 17, 284 AD. by the troops stationed in Nicomedia, Diocletian decideded to give a new structure to the Roman state that could guarantee greater security and timeliness of intervention in the defense of the shaky borders, give greater stability to the economy, avoid succession struggles. Therefore he thought it well to share power with a trusted general, Marcus Valerius Maximianus, who made Caesar in 285 and Augustus in 286, giving him the government of the West and instead reserving to himself the control of the richest and most advanced part of the Roman world, Orient.The newborn diarchy (government of two) was first of all functional to counter the threat of invasions from the north and eastern regions. The capital of the West was moved to Milan, a city closer to the border areas, and that of the East to Nicomedia (today's Izmit, on the Sea of ​​Marmara, in Asian Turkey). Each diarch had its own army, reorganized as a rapid intervention force capable of moving quickly in all crisis areas, if necessary even in those of not direct control. In order to provide an ideological basis to this new structure of the state, Diocletian established a hierarchy of command that drew inspiration from the celestial hierarchy: Maximianus got the same rank of Diocletian and became his "frater" (brother and therefore member of the Valerian gens to which Diocletian belonged - RIC VI p. 9) but his seniority was lower than that of Diocletian because, while Diocletian assumed the title of "Iovius", that is son of Jupiter, Maximianus that of "Herculius", son of Hercules, therefore further away from Jupiter for lineage. In 293, under the pressure of military events at the borders, Diocletian decided to further extend the project for the decentralization of the empire, flanking the two Augusti with two Caesars, with the task of garrisoning the northern borders (Britain and Gaul) and the Danubian ones. The empire was thus divided into four parts:
- Caius Aurelius Valerius Dioclezianus, Augustus senior, had the government of Thrace, Asia and Egypt;
- Gaius Galerius Valerius Maximianus was appointed Caesar of the Balkans, Thrace excluded, and therefore subordinate to Diocletian;
- Marcus Aurelius Valerius Maximianus, as junior Augustus, had the government of Italy, Spain and Africa;
- Flavius Valerius Costantius (also known as Costantius Chlorus), was appointed Caesar of Gaul and Britain and therefore subordinate to Maximianus.
In order to guarantee a natural line of succession, Diocletian decided that each Augustus, after 20 years of government, would give power to his own Caesar who, having become Augustus, would in turn appoint a trusted Caesar. Therefore, this was briefly, in the intentions of the one who had conceived it, the tetrarchy (government of four), a strongly decentralized organization of the state, but not without unity of command, in which the Augustus senior dictated the political and the others, Augusti juniores and Cesars, carried out the execution in autonomy of management. With the passage from the diarchy to the tetrarchy, the ideology of the system adapted itself: as Diocletianu and Maximianus Herculius were respectively sons of Jupiter and Hercules, so Galerius, through the institution of affiliation, became of Diocletian with the name of "Jovius" and Costantius of Maximianus, with the nickname of "Herculius". Both were conferred the title of "nobilissimus Caesar", both became part of the "gens Valeriana", all were mutually bound by the "pietas", the ethics of gratitude to the gods and affection for the consanguineous.
(4) IOV ET HERCV CONSER AVGG (IOVi ET HERCVli CONSERvatoribus AVGustorum -to Jupiter and Hercules protectors of the Augusti), to signify the collaboration of the Augusti and the Caesars in the management of the Empire.
(5)The mint mark is made up of the letter ε which identifies the officina number 5th of seven active in the period and the letters XXI which seem to allude to the percentage of silver in the alloy (20: 1). The dot after XXI is a characteristic sign of the issue.