CIMRM 497, 498, 499, 500 - Inscriptions and coins. Santa Prisca, Rome, Italy.

CIMRM 497. From: here.

CIMRM 498. The graffito. From here.

CIMRM 498. The graffito explained. From here.

CIMRM 498. From: here.

CIMRM 498 is found on the left-hand side of the cult-niche, and reads:

"Natus prima luce/duobus Augg(ustis) co(n)s(ulibus)/Severo et Anton(ino)/XII K(alendas) Decem(bres)/dies Saturni/luna XVIII"

I.e. "Born at dawn, the two Augusti Severus and Antoninus being consuls, 12 days before the kalends of December, Saturday, 18th of the moon." It indicates the date of initiation into the cult of someone, name unknown.

So it dates to November 20th, 202 A.D.¹

CIMRM entry

497.
Inscription on a marble slab (H. 0.24 Br. 0.63 D. 0.02).
Ferrua, 6. L.H. 0.04.
Deo Soli invicto Mithre(sic!) / quod saepe numini eius/ ex audito gratias e.....
Probably to be supplied with
et vota reddere moniti sunt.
498.
Graffito on the outside of the l. wall of the niche.
L.H. 0.05-0.06.
Natus prima Iuce / duobus augg. co(n)s(ulibus) / Severo et Anton[ino] / XII
k(alendas) decem[bres] / dies Saturni / luna XVIII.
20th November 202 A.D.
natus: I suppose a mystical sense.
499.
Inscription on a marble slab (H. 0.21 Br. 0.67 D. 0.02), walled in the ledge of bench p. L.H. 0.04.
Inv(ictis) (duobus) d(ominis) au(gustis).
500.
In the lower strata of sand of the Mithraeum, two coins of Commodus and one of his wife, Crispina, two of Diocletianus and one of Galerius, one of Constans and two of Valens were found. During the last excavations a coin of Claudius came to light.

Vermaseren-Essen, p.118: "The graffito has the form of a horoscope, though without mentioning the zodiacal symbols, and it is striking that the writer does not menton his name. There is a parallel for this in a genuine horoscope at Dura Europos, written on a wall of the workroom of a businessman in the "House of the Archives". ... it is clearly indicated that it was inscribed during the consulate of the two Augusti, Severus and Caracalla, i.e. in A.D. 202... The writer of the graffito on the cult-niche was natus on November 20th, A.D. 202, at the first light On the dies Saturni."