JANUS - The Beginning and the End(Roman) Twin-headed deity

  Found in 1970 during excavation of the Roman quarter of the city of Frejus in the Var department, France, this twin-headed, Hellenic-style bust measure 38 centimetres in height and dates from around the 2nd century AD. The face seen in profile to the left is a representation of Pan, god of Shepherds and flocks, while the right-facing profile is that of Hermes, herald and messenger of the gods and inventor of the lyre. The bust was probably imported into Frejus to adorn a public building or the garden of a villa.

Perhaps it was largely for etymological reasons, because the word 'initiation' suggests a door or gate, a threshold over which the neophyte passes in being admitted to a secret mystery, that Janus, Ovid's celestial 'janitor' who has the power to open and to close,41 was defined by George Wither, in his book of emblems, as the god of mysteries in general.42 But with perfectly good religious  logic, and with the cunning that distinguishes some of the emblem writers, Wither extended the character of the god to his votaries, and so the double face, originally meant for the janitor who protects the door, was transferred to those whom he lets in:

 He that concealed things will find

Must look before him and behind.

 Wind, Pagan Mysteries, p. 230 and notes 41 & 42:

41. Fasti I, 63-288; cf. Bocchi, Symbolicae quaestiones, no. cli: "Ianitor immensus superis et manibus imis.' How widely this mystery could be expanded is shown by the Janus frieze over the entrance to the Medici villa at Poggio a Caiano, a Neoplatonic monument of the first importance, on which see A. Chastel, Art et humanisme a Florence au temps de Laurent  le Magnifique (1959), pp. 217-25.

 42. George Wither, Emblems (1635), p. 138. 

In the Classical era, Janus was commonly shown as carrying two keys, one of gold and the other of silver, to open and lock each of the two solstitial gates, the Janua Coeli and the Janua Inferni, corresponding respectively to the Winter and Summer solstices (i.e., the two extreme points of the Earth’s annual cycle around the Sun).  Janus, as Master of Time, was the Janitor who opened and closed this cycle. On the other hand, he was also the god of initiation into the Greater and the Lesser ‘Mysteries’.

The word ‘Initio’ comes from the root-word ‘in-ire’ (= ‘to enter’ and this is clearly connected with the concept of a gateway).  According to one, rather obscure passage in Cicero’s treatise De Natura deorum, the name ‘Janus’ had the same root as the verb ‘ire’ (= to go) and this root-word has been detected in Sanskrit texts where among its derivatives is the word ‘yana’ (= the way).  According to most linquists, it seems that that word ‘ianus’ is based on the root ‘ia’.   This is an extension of an Indo-European root ‘ei’ (= ‘to go’) an this abstract term signifies ‘passage’ or ‘travelling’.  The ancient Oriental concept of ‘Tao’ means literally ‘the way’ and is shown in Mandarin Chinese by two ideographic characters which are the signs for the head and the feet (i.e., the beginning and the end).   Furthermore, you will recall that Jesus proclaimed Himself to be ‘the Way’.  It is interesting, and not entirely inapposite, I suppose, that the symbol of the two keys is retained, even to this day, by the Papacy in its Coat of Arms.  Incidentally, another symbol for Janus was that of a barque, a vessel that appropriately could move backwards and forwards - corresponding to Janus’s two faces - and this is also retained today as one of the other chief symbols of the Papacy.

Stewart, Trevor, Some Thoughts about the Roman God Janus

http://www.canonbury.ac.uk/library/lectures/some_thoughts_about_the_roman_go.htm

THE TWO FACES

The Mantegna (1470) introduces the first image of Prudence, a woman holding an elaborate mirror in her left hand, a caliper in her right. She has a Janus head--young female face looking forward, older bearded male face looking back. This symbol is usually employed to suggest sober reflection in the light of past experience. The same face also appears on the Mantegna Theologia card, implying that the state of mind behind those two faces participates in two worlds at once, presumably with the "feminine" side in the world of spirit and the masculine side in the world of matter.