Constantine I as Caesar (306-307 A.D.) -  AE Follis - 28mm, 8.92gr
Constantine I, his laureate head right.
Reverse - GENIO POPV-LI ROMANI                              
Genius standing left, modius on head, naked but for
chlamys over left shoulder, holding patera (from which
liquor flows) in right and cornucopiae in left hand.
B in right field, ANT : in Exergue.

The images below were photographed by Beast Coins (top) and Gert Boersema Ancient Coins (bottom) respectively.
The image above is my own scan.
Minted at officina B in Antioch (Antakya, Turkey) between July 306 and early spring 307 A.D.

Voetter, Otto, "Die Münzen der römischen Kaiser, Kaiserinnen und Caesaren von Diocletianus bis Romulus, Katalog der
hinterlassenen Sammlung und Aufzeichnung des Herrn Paul Gerin" (Voetter-Gerin), 1921, Constantine Magnus, #1
(specimen in the collection of Paul Gerin, from officina A, Γ and S)
-Kent, J.P.C., "The Pattern of Bronze Coinage under Constantine I", Numismatic Chronicle, 1957, p 69, #1086
-Sutherland, C.H.V., "The Roman Imperial Coinage" Volume VI, 1967, p624, note 5: "This issue, save for Constantius,
continued without change at the beginning of Group III, except that no coins of Severus as Augustus (though included
by Kent, N.C. 1957, p. 69, no. 1084) are known to me".
-Sutherland, C.H.V., "The Roman Imperial Coinage" Volume VI, 1967, p627, Note: "As indicated above, p. 624, n. 5,
the aes of Group II (ii) continued into Group III with unchanged Genio Populi Romani folles for Galerius and Maximinus
(though probably not for Severus as Augustus)....".
-Bastien, Pierre, "Trouvaille de folles au Liban (294-307)", Revue Numismatique, 1967, Aleppo & Homs, Syria Hoards, table p171.
-Bastien, Pierre, "Trouvaille de folles au Liban (294-307)", Revue Numismatique, 1967, Lebanon Hoard, p188, #76.
-King, C.E. & Spaer, A., "A Hoard of Folles from Northern Sinai", Numismatic Chronicle, 1977, p106, #4000-4009.
-Salzmann, D., "Folles of Severus II as Augustus and of Constantine I as Caesar from Antioch ", Numismatic Chronicle, 1983,
p214-216 and plate 42, #7.

See my page on Constantine I as Augustus - The "lost" Genio Populi Romani issue from Antioch
This is ex-Gert Boersema Ancient Coins and ex-Beast Coins and is featured at Not in RIC.

Quality: about Very Fine / good Fine
Rarity: Unclear. So far I have been able to confirm the existence of at least 7 specimens of this coin from
officina B, so according to the definition of RIC Vol VI, that would make it's rarity R3.