A detail from the Maestà altarpiece, this scene depicts the moment of the Incredulity of Saint Thomas, rendered in the refined style of the Sienese School.

This work is a panel from the reverse side of the Maestà, the monumental altarpiece commissioned for the Siena Cathedral. Duccio di Buoninsegna, a central figure of the Sienese School, demonstrates his mastery of narrative clarity and emotional expression within this scene. The composition depicts the moment when Thomas the Apostle touches the side of the resurrected Christ to verify the wounds of the crucifixion.

Duccio employs a sophisticated use of colour and drapery to define the figures. The heavy, sculptural folds of the robes, rendered in shades of blue, green, and deep red, provide a sense of volume that departs from the flatter Byzantine traditions of the era. The figures are arranged in a shallow, architectural space, with the arched doorway acting as a frame for the interaction between Christ and Thomas. The golden halos, a hallmark of the period, unify the group while individualising the expressions of the surrounding disciples, who observe the event with varying degrees of contemplation and surprise.

Technically, the work displays the precision of tempera painting on wood. The application of gold leaf, though partially visible in the halos, reflects the light and adds a sense of sanctity to the scene. The anatomical treatment of the figures, particularly the hands and feet, shows an attempt to move toward a more naturalistic representation of the human form. This panel remains a primary example of early Italian painting, capturing the transition between medieval stylisation and the burgeoning humanism that would characterise the later Renaissance. The focus remains on the psychological exchange between the participants, articulated through gesture and gaze rather than complex spatial depth.