On the south side of the Piazza del Campo in Siena is the Palazzo Púbblico (Town Hall), an imposing Gothic building of travertine and brick (1288-1309). The top floors of the lower side wings were added in 1680. The construction of the palazzo involved much upfilling and extensive underbuilding. The facade is relieved by rows of elegant windows and cornices of round-headed arches and topped by battlements. The black and white escutcheon of Siena, the Balzana, is constantly repeated in the arches over the windows. At either end of the central block is a campanile, and under its battlemented top is a roundel with Christ’s monogram (IHS), the distinctive attribute of San Bernardino of Siena (1380-1444), who preached in the Piazza del Campo. In the center of the first floor is the coat of arms of the Médici (who from 1569 were Grand Dukes of Tuscany).