Saint John, Apostle and Evangelist - Duomo of Lecce

Oval painting on canvas with gilded wooden frame in the presbytery of the Duomo of Lecce.
Saint John the Apostle writes on a scroll sustained by an angel who holds the inkwell. In the background, on the right, there is the eagle, attribute of the Evangelist; on the left, an angel offers a prayer and another one holds a chalice from which a snake emerges.
The tradition of the chalice with the snake related to Saint John comes from an anecdote regarding his life: it is said that, while in Ephesus, John was offered a glass of poisoned wine. Before drinking, he blessed the drink and the poison came out of the cup in the form of a green snake.