The identity of this distinguished saint remains uncertain. It is probably St Agatha, a Sicilian Christian martyred by having her breasts torn off and whose killing is discreetly hinted at by the unfastened garment. The painting was part of a dismembered polyptych of which 5 panels remain. Our saint was portrayed looking towards the central image of the Madonna and Child, so she stood on the left side of the altar. The work is attributed to Pietro Lorenzetti. Born in the same generation as Simone Martini, he studied under Duccio, along with his younger brother Ambrogio. Following in the footsteps of their master, the Lorenzettis took the art of icon-making in the direction of a Gothic culture that combined stylisation and a commitment to realism. The two brothers were key players in the development of landscape painting and a new three-dimensional approach to space, especially in their frescoes.

The polyptych to which this work belongs is dated circa 1315, at the beginning of the artist’s career. The arched frame retains the style of the Duecento (13th-century Italy). As with all panels identified in the altarpiece, the halo is incised in the preparatory layer, a procedure abandoned after 1320 when Pietro adopted an engraver’s point, following the example of Simone Martini.

The work cultivates the Sienese taste for linearity and stylisation, especially in the hand with its slender fingers holding the cross, the fluidity of the ribbon on the neck and shoulder of the saint and the armholes hemmed with a black braid. The taste for elegant detail is displayed in the sculpted hair, the curious buttons adorned with beads and the oriental-inspired embroidery of the undergarment. These elements reflect the fashions of the Sienese elite of the day. They present the saint in a contemporary, concrete and aristocratic fashion, though she lived in the third century, thus making the depiction much more accessible to the faithful. The intensity of St Agatha's gaze testifies to the search for an expressive style cultivated by Pietro Lorenzetti.