The Piazza del Comune is the medieval heart of Prato, a handsome square lined by the Gothic Palazzo Pretorio, the cathedral facade, and the loggia of the Comune. The square functions as the social centre of the city — market mornings, evening passeggiata, festivals. At its centre stands a bronze statue of Francesco Datini, the 14th-century wool merchant who made Prato's fortune and who is the subject of Iris Origo's wonderful biography, The Merchant of Prato.
Datini was one of the most successful merchants of the medieval world, and his archive — 150,000 letters and business documents preserved in a warehouse in Prato — is one of the greatest sources for the economic and social history of the late Middle Ages. The Palazzo Datini nearby is still intact and can be visited. Stand in the square and you are standing in one of the best-documented economic histories in Europe.