Lorenzetti was commissioned in 1338 to paint the four walls of the council chamber with a programme that the Nine could read while deliberating. The result occupies three of the four walls: the allegorical figures of Justice, Concord, and Common Good on the north wall; the effects of good government in the city and the countryside on the east wall; and the effects of tyranny on the west wall. The fourth wall is a window onto the actual countryside.

The cycle is also the first surviving large-scale Italian landscape painting — the Sienese contado, with its hills, vineyards, hilltop towns, and the trade roads connecting them, painted not as backdrop but as the object of governance itself.

The Sala dei Nove is open as part of the Museo Civico di Siena, in the Palazzo Pubblico on Piazza del Campo. Tickets include access to the rest of the museum and to the Torre del Mangia. The frescoes have been conserved several times; the most recent campaign concluded in 2022.