Siena was, together with Florence, the political, economic, and cultural leader in the center of Tuscany during the late Middle Ages and early Renaissance. Siena became part of the Grand Duchy of Tuscany under Medicean dynasty just in 1559, but the major heyday period was doubtless the two centuries before, under the oligarchy. Despite the plague of 1348 that killed over than a half of population, this was a time of peace and prosperity during the city had alliance with the papal party of the Guelphs and contacts with the Angevin dynasty in France and Naples. These political and cultural alliances influenced the born and development of Sienese painting and than produced the Western Europe gothic style.
During the Middle Age two cities only was able to produced great painting schools: Florence and Siena. But in front of the austerity and rigor of Florence art, Sienese painting introduced lyrical note and a refined sense of color depicting figures with more like-life proportion and shading as well. The sense of narration suggested by natural, three-dimensional and perspective elements of forward styles (Renaissance on top) owed much to techniques introduced by Sienese painting.
Sienese painting school was born doubtless with Duccio di Buoninsegna , who, together with Giotto, was an important figure in the development of all Western art too. Although Duccio was strongly influenced by the Byzantine Art, he was the first to introduce features proper of whole Sienese school. Other figures of this school, in fact, were all pupils of the master Duccio: Simone Martini and brothers Pietro and Ambrogio Lorenzetti. However one of each was important for the development of Sienese painting, Simone Martini introducing frescoes in the art of tuscan city, Pietro Lorenzetti with his study on deep and complex spatial settings and three-dimensional figure construction, Ambrogio who was perhaps the first in Europe to employ a single-point perspective.
The most important work of Sienese painting is perhaps the Maestà, ascribe to Duccio di Buoninsegna but where either Simone Martini or Pietro Lorenzetti worked on. The Maestà is an altarpiece comprising 84 individual panels which depicts The Virgin enthroned with the Christ Child surrounded by Twenty Angels and Nineteen Saints. The works was commissioned by the Siena Cathedral in 1308 and it was completed in 1311. Today most of this elaborate double-sided altarpiece is in the cathedral museum but several of the predella panels are scattered outside Italy in various museums.