A refined tempera panel by Sienese master Andrea Vanni, depicting Saint Mark in the act of writing his Gospel with characteristic fourteenth-century grace.

This depiction of Saint Mark by the Sienese painter Andrea Vanni reflects the stylistic conventions of fourteenth-century Italian art. Vanni, a contemporary of Bartolo di Fredi, operated within the tradition of the Sienese School, which prioritised decorative grace and linear elegance over the more sculptural, volumetric approach favoured by Florentine contemporaries. The figure of the Evangelist is presented in a half-length format, a common arrangement for devotional panels intended for private or ecclesiastical use.

The saint is shown in the act of writing, his gaze directed slightly away from the codex, suggesting a moment of divine inspiration. His features are rendered with the characteristic soft modelling of the period, while the drapery of his robes follows a rhythmic, flowing pattern. The halo, a prominent feature of the composition, is executed with fine punchwork, a technique frequently employed by Sienese masters to create light-reflecting surfaces that suggest a celestial presence. The overall composition is balanced and restrained, focusing the viewer's attention on the act of recording the Gospel.

Andrea Vanni was not only a painter but also a significant political figure in Siena, serving as a member of the Council of Nine. His artistic output is marked by a consistency of style that bridges the gap between the earlier influence of Simone Martini and the later developments of the Quattrocento. This work provides a clear example of the technical precision found in Sienese tempera painting, where the application of pigment and gold leaf was managed with extreme care to ensure both durability and visual clarity. The focus remains on the spiritual gravity of the subject, conveyed through the deliberate posture and the careful handling of the manuscript, which serves as the primary attribute of the Evangelist.