Florence, Museum of the Opera del Duomo (Museum of Florence Cathedral of Santa Maria del Fiore): “The Cross of the Treasure of St. John: the verso.”Detail with "sphinx", a monster half lion and half man, which in Christian iconography represents the enigma of a question to which there is no answer. Symbol of fate and mystery.The Cross  is a splendid example of Renaissance jewelery, sculpted in silver foil, chiseled and enameled by Betto di Francesco Betti, Antonio del Pollaiolo and Miliano di Domenico Dei between 1457 and 1459 approximately. It was commissioned to complete the silver altar. The Cross-monstrance is made up of three distinct main parts: the Crucifix, the stem and the base.