Piero-di-cosimo Jean l'évangéliste

A youthful, red-haired Saint John the Evangelist is depicted in a blue tunic and red cloak, framed by a stone niche. He raises his right hand in a sign of blessing over a golden chalice, while a small, dark serpent coils and rises from the cup's rim. This visualizes the legend of the poisoned cup, where John's faith rendered a lethal drink harmless.

The motif of the serpent in the chalice represents the neutralization of poison, a concept central to both Christian hagiography and the alchemical pursuit of transmuting the 'toxic' prima materia into spiritual medicine. Piero di Cosimo's eccentric style was developed in the intellectual milieu of Florence during the height of the Neoplatonic revival led by Marsilio Ficino.