The Palazzo Pubblico of the city of Siena, also known as Palazzo Comunale (Town Hall), was built around 1310 by the Government of the Nine of the Republic of Siena to be its headquarters. It overlooks Piazza del Campo, which has paving with segments that divide into nine parts, precisely as a symbol of the Government. The Torre del Mangia is alongside the Palace and was enlarged on the left side in a southerly direction when the first floor was built to contain the Prisons. These were followed by the Grand Council hall on the upper floors, which became the Teatro dei Rinnovati in the 16th century, the oldest heatre in Siena, where Charles V was welcomed and celebrated in 1536. The Cappella di Piazza was built to thank the Virgin Mary for the end of the terrible plague that had struck Siena in 1348. A canvas painted by Sano di Pietro, representing San Bernardino in Piazza del Campo, gives us a view of the Palace at that time. Unlike today, it now devoid of the top floor, the two lateral wings and the bell gable on the left, elements that were only added in 1680 by Carlo Fontana.
Still today, the Palace is the headquarters of the Municipal Authority. The Mayor's offices and the reception rooms are located inside it; the decorations have been perfectly preserved since the fourteenth century, when the Government of the Nine secured the work of the major artists of the time, to demonstrate and paint its political programme. In the room dedicated to them, there is the famous fresco by Ambrogio Lorenzetti, depicting the Effects of Good and Bad Government. The Civic Museum is located on the first floor and it contains famous works by Simone Martini, Duccio di Buoninsegna, Giovanni Antonio Bazzi (aka Sodoma) and Domenico di Jacopo di Pace (aka Beccafumi); the Town Council room is located on the second floor, as is the loggia, which looks out towards the rear side of the building itself, in a southerly direction.