In the first chapel, entering from the left we find the Baptistery, a very simple element formed by a tub with its foot in limestone from the fifteenth century, and a wooden roof with a door decorated with the representation of the Baptism of Christ dating back to 1837.
On the bare wall there is a modest canvas with a large frame, representing the evangelical Transfiguration of St. Matthew. In the center, in a halo of light, the standing figure of Christ dominates, with his eyes turned to the sky, his arms outstretched, with Moses and Elijah at the sides, the first seated, with his right hand pointing to the two tables, the second kneeling. At the foot, amazed by the extraordinary event, the Apostles Peter, James the Greater and John are represented
The Christ, weighed down by the red cloak forcibly displaced and by the redundant tunic of folds, was represented by the unknown local painter of the mid-seventeenth century in a different way from what is described in the Gospel. This can also be seen in the account of a holy visit made on April 7, 1660, when the canvas was placed in the Cappellone del Crocifisso, under a window that opened into the church, from which the Bailiffs followed the sacred functions.