The building, ancient seat of political and military power, is an important evidence of Campiglia's late medieval period and shows the influence of two dominant Tuscan cities, Florence and Pisa. The original facade is made of two white-grey limestone arches in which an inscription indicates that the building was erected in 1246. The upper part of the facade is enriched with 72 heraldic emblems that date from 1406, year in which Campiglia passed under the rule of Florentine Republic.