Symbolism refers to Greek, Latin, Christian, pagan, and alchemical themes, but only, the latter, to the extent dictated by the historical period of its realization. The "alchemical" call lies all in the power of love, capable of magically transforming, esoterically, the subjects who love each other. The two faces above the Arch can be traced back to Dionysus and Arianna, an expression of Christ's bond and the Church, confirmed by the underlying indication "UNA (DEAR?)" a single flesh, as recalls the letter of St. Paul the Apostle to the Ephesians, directed at the duties of wife and husband.