Access to the Museo Civico, the city museum of Siena, is from the superbly proportioned gothic courtyard of the Palazzo Pubblico. Founded in the 1930s, the Museo Civico contains some of the finest paintings, sculptures and frescoes of the renowned Senese School.Two flights of stairs lead up to the Sale Monumentali grand chambers of the museum. Immediately to the right is the Sala del Mappamondo, formerly used as the meeting room for the General Council of the Republic of Siena. The room takes its name after a rotating map, now lost, painted by Ambrogio Lorenzetti, that showed the lands governed by the city. On the far wall of the chamber is a Maestą fresco by Simone Martini, painted between 1312 and 1315, still striking today on account of its delicate use of the chromatic palette and its purity of lines. This is regarded as being the first real masterpiece by Simone Martini, who in 1328 also painted the portrait of the condottiero Guidoriccio da Fogliano, who seized the Castle of Montemassi.