The art of the region of Tuscany in the late 13th century was dominated by two masters of the Byzantine style, Cimabue of Florence and Duccio of Siena. Their commissions were mostly religious paintings, several of them being very large altarpieces showing the Madonna and Child. These two painters, with their contemporaries, Guido of Siena, Coppo di Marcovaldo and the mysterious painter upon whose style the school may have been based, the so-called Master of St Bernardino, all worked in a manner that was highly formalised and dependent upon the ancient tradition of icon painting. In these tempera paintings many of the details were rigidly fixed by the subject matter, the precise position of the hands of the Madonna and Christ Child, for example, being dictated by the nature of the blessing that the painting invoked upon the viewer. The angle of the Virgin's head and shoulders, the folds in her veil, and the lines with which her features were defined had all been repeated in countless such paintings. Cimabue and Duccio took steps in the direction of greater naturalism, as did their contemporary, Pietro Cavallini of Rome. Giotto, (1266–1337), by tradition a shepherd boy from the hills north of Florence, became Cimabue's apprentice and emerged as the most outstanding painter of his time. Giotto, possibly influenced by Pietro Cavallini and other Roman painters, did not base the figures he painted upon any painterly tradition, but upon the observation of life. Unlike those of his Byzantine contemporaries, Giotto's figures are solidly three-dimensional; they stand squarely on the ground, have discernible anatomy and are clothed in garments with weight and structure. But more than anything, what set Giotto's figures apart from those of his contemporaries are their emotions. In the faces of Giotto's figures are joy, rage, despair, shame, spite and love. The cycle of frescoes of "the Life of Christ" and "the Life of the Virgin" that he painted in the Scrovegni Chapel in Padua set a new standard for narrative pictures. His "Ognissanti Madonna" hangs in the Uffizi Gallery, Florence, in the same room as Cimabue's "Santa Trinita Madonna" and Duccio's "Ruccellai Madonna" where the stylistic comparisons between the three can easily be made. One of the features apparent in Giotto's work is his observation of naturalistic perspective.