While working over the Wikipedia Mithras article, I found mention of syncretism with the Orphic deity Phanes. It seems that we learn of this from inscriptions; but also that there is literary evidence of the syncretism of Mithras and Phanes, in the proverbs of Zenobius. The reference is: ”Proverbia” 5.78 (in Corpus paroemiographorum Graecorum vol. 1, p.151) This is Century V, 78 of Zenobius’ work. The reference comes from Manfred Clauss’s splendid book on Mithras, p.70 n.84. In the Google books PDF it is p.208. But… I don’t see the name of Phanes here. I see a list of deities; the name of Mithras is among them. Can anyone with more Greek than me help?
I have posted about this obscure 2nd century proverb collector before. His work doesn’t exist in English, and yet here again are interesting snippets on antiquity.
UPDATE: Fortunately I find more information in Albert de Jong, Traditions of the Magi: Zoroastrianism in Greek and Latin literature, p.309:
A final text that must be discussed is a list of elements attributed to an unknown Evandrus by the excerptor Didymus Zenobius 5.78. “Evandrus said that the gods who rule over everything are eight: Fire, Water, Earth, Heaven, Moon, Sun, Mithra, Night.” The appearance of Mithra in this list suggested to some an Iranian background to this passage. An almost identical list can be found in Theon of Smyrna, but there instead of Mithra we find the name of Phanes. In an interpretation of these passages, Reitzenstein invoked the importance of the Elements in Manichaean and Zoroastrian literature, and concluded that the lists of elements were typical for Iranian religions.
Both phrases, however, are concerned wilh the proverb “All is eight” …; this ogdoad is divided into a monad and a heptad. There can be no doubt that the lists are Greek; more particularly, they have an Orphic background. This is not only evident from the reference to the Night in both lists of eight elements, but particularly from the reference to Phanes. It is well known that Phanes and Mithras were connected with each other in the context of the Mithraic mysteries. There is not only icono-graphic evidence for this identification, but also textual evidence, from a famous Mithraic inscription to Zeus-Helios-Mithras-Phanes. Theo of Smyrna also explicitly introduces the list as deriving from Orphic literature.
226. Theo Smyrnaeus, p. 104, 20 Hiller.
228 CIMRM 475; for Mithras and Phanes, cf. H.M.Jackson, “Love makes the World go round: The Classical Greek Ancestry of the Youth with the Zodiacal Circle in Late Roman Art’, in Hinnells (ed.). Studies in Mithraism 131-164.
This seems to be the evidence; without the inscriptions, it would probably not be very good. It would be nice to track down Theo of Symrna, tho.