It is thought that Martini was a pupil ofDuccio di Buoninsegna, the leading Sienese painter of his time. According to late Renaissance art biographerGiorgio Vasari, Simone was instead a pupil ofGiotto di Bondone, with whom he went to Rome to paint at theOld St. Peter's Basilica, Giotto also executing a mosaic there. Martini's brother-in-law was the artistLippo Memmi. Very little documentation of Simone's life survives, and many attributions are debated by art historians. According to E. H. Gombrich, he was a friend of Petrarch and had painted a portrait of Laura.
Simone was doubtlessly apprenticed from an early age, as would have been the normal practice. Among his first documented works is theMaestà of 1315 in thePalazzo Pubblico inSiena.[1] Lippo Memmi painted a similarMaestà for the Palazzo Comunale inSan Gimignano shortly afterwards, an example of the enduring influence Simone's prototypes would have on other artists throughout the 14th century. Perpetuating the Sienese tradition, Simone's style contrasted with the sobriety and monumentality ofFlorentine art, and is noted for its soft, stylized, decorative features, sinuosity of line, and courtly elegance. Simone's art owes much to Frenchmanuscript illumination and ivory carving: examples of such art were brought to Siena in the fourteenth century by means of theVia Francigena, a main pilgrimage and trade route from Northern Europe to Rome.