He began his work in 1337.
A similar mode of symbolising the Commune is chosen in the bas-reliefs of Archbishop Tarlati's tomb at Arezzo, where the discord of the city is represented by an old man of gigantic stature, throned and maltreated by the burghers, who are tearing out his hair by handfuls. Over this figure is written "Il Comune Pelato."
These were adopted as the ensign of Siena, in the Middle Ages.
In the year 1336, just before Ambrogio began to paint, the Sienese Republic had concluded a league with Florence for the maintenance of the Guelf party. The Monte de' Nove still ruled the city with patriotic spirit and equity, and had not yet become a forceful oligarchy. The power of the Visconti was still in its cradle; the great plague had not devastated Tuscany. As early as 1355 the whole of the fair order represented by Ambrogio was shaken to the foundation, and Siena deserved the words applied to it by De Commines. See Vol. L, Age of the Despots, p. 162, note 2.