This square, pounding heart of the medieval city, was opened at the beginning of 1200 during the construction works of the Palatium Communis Bononiae, now Palazzo del Podestà. The core of the City Hall located in the western part of the square, dates back to 1287. In 1390 the building works of the large Basilica of Saint Petronius started, strongly wanted by the Municipality of Bologna and designed by Antonio di Vincenzo. The Banchi arcades, made by Jacopo Barozzi as known as “il Vignola” in 1568, close the eastern side of the square and hide the medieval district of the market (Mercato di Mezzo), once made of decaying wooden and crick houses. Since its origin Piazza Maggiore has always staged protests, markets and clashes.