Along the left nave, within an elaborate neo-medieval tabernacle dating back to the 1920s, is an image of the Madonna with Child enthroned between Saints John the Baptist and Sebastian. On the sides, there are depictions of the Beheading of Saint John the Baptist and the Martyrdom of Saint Sebastian. This fresco is described in detail in the mid-19th century in the Memorie of the proposed Luigi Luciani, when it was discovered behind an altar and immediately concealed from view.
In the center is the Madonna seated on a monumental throne with a small apse-like structure, featuring a shell-shaped basin resting on a sculpted pedestal. The Virgin, dressed in a rose-colored robe and originally blue mantle, holds the robust Child on her lap. The Child is depicted nude, holding a goldfinch in one hand and wearing a coral amulet around his neck, symbolizing protection against the evil eye (apotropaic).
To the left of the throne, Saint John the Baptist is portrayed wearing a skin garment, with a large pink-violet and green mantle, holding the banner of the Cross and the customary scroll with the inscription “ECCE AGNUS DEI” . To the right, Saint Sebastian is depicted as a young nobleman in a green tunic and red cloak, holding the martyr’s palm and arrows. Both saints are shown standing and facing forward.
On the side, there are scenes of martyrdom: on the left, the executioner places his sword back in its scabbard after beheading John within the courtyard of Herod’s palace, depicted as a medieval crenellated building. In the background, Salome is shown wearing an elegant and refined Renaissance dress, with blonde hair cascading over her shoulders and holding a wicker basket. The executioner wears a green tunic lined with red, cinched at the waist, and high boots. On the opposite side, Saint Sebastian, bound to the post of the scaffold, is struck by numerous arrows shot by four archers; above, an angel receives his soul to present it to God.
In the upper lunette, set in a rocky landscape with some trees, grass bushes, and a small pond, perhaps symbolizing the Jordan River, with marsh plants.At the center, Saint John the Baptist is depicted preaching and baptizing his followers (the fresco is damaged, and only five figures can still be recognized). On the left, within the wall’s thickness, is Saint Eustace holding a stag with a cross between its antlers. The saint, patron of hunters, is dressed as a warrior, with a sword.
In the spandrel, within lacunary polylobed shapes, are depicted the dove of the Holy Spirit, the four Evangelists, alternated by angels, dating back to the 1920s, when Castellucci illuminated the fresco and restored the chapel. Originally, as attested by the 19th-century description, there were “Figures of Religious Saints from different Orders,” which had evidently deteriorated or been destroyed in the 1919 earthquake.
The work, dating from the 1460s and attributed by Manola Rosadini to the circle of the Valdarno painter Mariotto di Cristofano (1393-1457), can, however, be linked to a Florentine artist connected to Domenico di Michelino (1417-1491), a pupil of Fra Angelico, or a follower of Benozzo Gozzoli (ca. 1421-1497). Our painter, while presenting a Renaissance spatiality with figures set in perspectival scenes, nonetheless shows traces of a more archaic style still in use.
— Licia Bertani
