GENIOPOPROM

The GENIO POP ROM type was introduced by Constantine as Caesar.

Constantine, Caesar July 306 - July 307
28-26 mm.
FL VAL CONSTANTINVS NOB C
GENIO POP ROM
S A
PTR
RIC VI Trier 719b, Struck "c. summer 307"

Notice the "draped loins" which was new. (Compare to Genius on the next coin which is of the previous type.)

The GENIO POP ROM type was struck for Constantine as Caesar and Augustus, Galerius as Augustus, Maximinus II as Caesar and Augustus, and Maximian as Senior Augustus. There are also very rare examples for Maxentius (Ludunum only) and Diocletian as AETER AVG (Lugdunum only).

Coins with legend GENIO POP ROM are later and smaller versions of the main coin type of Diocletian's coin reform of c. 294 which introduced the follis of the very common GENIO POPVLI ROMANI type (to the right). This type was continued into the second tetrarchy after 305 and was still being issued when Constantine was given imperial power in July 306 by the army upon the death of his father, the emperor Constantius.

Coin the the right: Constantius as Caesar at Trier. 27 mm. 9.35 grams. RIC VI Trier 594a, struck c. 303- 1 May 305.
CONSTANTIVS NOBIL C, laureate, cuirassed bust right.
GENIO POPVLI ROMANI, Genius standing left, holding out patera with cornucopia, S left and F right. PTR in exergue.

In summer 307 the mints of Constantine replaced the GENIO POPVLI ROMANI type with an otherwise similar type (next) with
• shorter legend GENIO POP ROM
• smaller diameter and lesser weight, and one difference in the artwork:
• Genius has his lions draped (Previously Genius was wearing only a chlamys over his left shoulder and was naked otherwise. See the Constantius coin.).

Emperors.

Galerius as Augustus.

Galerius
26 mm. 6.63 grams.
IMP MAXIMIANVS PF AVG [Identical with a legend sometimes used by Maximian]
GENIO POP ROM
S A across field
PTR in exergue
RIC VI Trier 714. Struck c. summer 307. This issue is shared with Constantine and dated to "autumn 307-end of 308." Remarkable, this exact same obverse legend is used in this RIC group for Maximian as active augustus. However, this portrait looks like Galerius rather than Maximian. So this coin apparently belongs to Galerius.

Maximinus II, eastern Caesar.
25 mm. 6.28 grams.
S A
PTR in exergue
RIC VI Trier 720a "c. summer 307"

Maximian as Senior Augustus.

Maximian as "Senior Augustus," his title after his retirement and before his second reign.
25-24 mm. 6.61 grams
IMP MAXIMIANO PF S AVG
("S" for "Senior")

GENIO POP ROM
PLN in exergue
RIC VI London 90, "c. summer 307"

Maximian, "autumn 307-end of 308." Second reign.
27-25 mm. 7.18 grams.
The long obverse legend was used to distinguish Maximian from the emperor we call "Galerius," Galerius Maximianus, who had sometimes used the exact same short legend with "MAXIMIANVS" that Maximian had used.
IMP C M AVREL MAXIMIANVS PF AVG
"M AVREL" makes it Maximian (as does the portrait).
GENIO POP ROM
S A
PTR
RIC VI Trier 766.

Licinius
20 mm. 2.89 grams.
At the end of 308 at the Conference at Carnuntum it was decided to declare Maxentius a "public enemy" and raise a new man, Licinus, to Augustus in the west. This elevation was after the GENIO POPVLI ROMANI type had been discontinued and replaced by the similar, but lighter, GENIO POP ROM type with its shorter legend.
Also, by this time the size of the GENIO POP ROM coins was much reduced--down to 20 mm instead of 26 mm.
T F
BTR in exergue
RIC Trier 120. Schulten plate 5.12 "308-9"

Licinius had no GENIO POPVLI ROMANI coins in the west, however, there was a revival of that legend on small (21 mm) and rare coins only from Alexndria after 312 which are only for Licinius and Constantine.

Licinius
21-18 mm. 2.73 grams.
IMP LICINIVS P AVG
GENIO POP ROM
TF ✳
PLG
RIC VII Lyons 49 "r5, 315-6."
This is the last GENIO POP ROM issue at Lyon. The field marks are almost exclusively on SOLI INVICTO COMITI coins of Constantine, with the exception of Licinius on three (because of different obverse legends) "r5" and "r4" GENIO POP ROM numbers for Licinius only. After the death of Maximinus II in 313 Lyon was issuing SOLI INVICTO COMITI for Constantine and GENIO POP ROM only for Licinius.

Mints. The type was issued only at the western mints. It is common from Trier, London, and Lugdunum. From Arles it is extremely rare, issued for Constantine only 315-316. From Ostia it was issued after the fall of Maxentius Oct. 28, 312, for Constantine, Maximinus II, and Licinius, until the mint closed in 313.
Trier continued it until c. 316 for Licinius, but c. 310 replaced it by SOLI INVICTO COMITI for Constantine. London is much the same, but still issued some GENIO POP ROM coins for Constantine until c. 316. Lugdunum is as Trier, with the addition of very rare types for Diocletian as AETER AVG and for Maxentius. It was apparently temporarily closed c. late 309 and reopened after the defeat of Maxentius. After that, at Lugdunum Constantine had completely switched to SOLI INVICTO COMITI and GENIO POP ROM is only for Licinius and very rare (as above).