Constantine I 'the Great' Æ Nummus. Constantinople, AD 327. CONSTANTINVS MAX AVG, laureate head right / Labarum, with three medallions on vexillum and surmounted by Christogram, piercing serpent below; SPES PVBLIC across fields, A in left field, CONS below.Very Rare.
From the inventory of a UK dealer.
The reverse of this nummus, remarkable for being Constantine's earliest use of Christian symbolism on his regular coinage, has been the subject of academic discourse for decades. The first numismatic instance of Constantine's use of the Chi-Ro symbol was in a series of medallions struck after his victory at the Battle of the Milvian Bridge in AD 312, where he famously experienced a vision featuring a 'cross of light in the heavens, above the sun' (Eusebius, Life of Constantine, 1:28), the wearing of which would lead his troops to victory. Peter Weiss has convincingly argued that the physical phenomena that was witnessed that day was likely a parhelion, which rather like eclipses may have been responsible for more than one inspirational pre-battle vision throughout history (Weiss, 'The Vision of Constantine' in Journal of Roman Archaeology: 16, 2003). Whatever the wordly cause, Constantine's intentions following this event are what have caused controversy.
According to Weiss, rather than experiencing an immediate revelation Constantine only interpreted this vision as Christian years later, which explains the long delay and very small proportion of coins featuring Christian imagery. Another interpretation of these events argues that Constantine was actually pursuing a deliberately slow strategy, in order to not stir resistance – particularly given the civil wars which already troubled his reign (DesRosiers and Vuong, Religious Competition in the Greco-Roman World, 2016). However, as early as 1962 (even before the publication of the relevant RIC volume) numismatic historian Richard Bruun expressed scepticism that the sign of the Chi-Ro would have been recognised as religious, in his seminal article 'The Christian Signs on the Coins of Constantine'. The wider 'pagan' audience who handled coins of this type would have instead recognised it as a personal badge of the emperor - in this example, it is certainly presented as such in its placement atop the vexillum, where the medallions stand in for portraits of the imperial family.
The meaning of the snake suffers from similar ambiguities surrounding its meaning and reception. Depending on an author's views on the overtness of the other Christian imagery present, the snake can be interpreted either as a 'universal' symbol of evil, a representation of the recently-defeated pagan Licinius I, or a Judeo-Christian image of the demonic.