Piazza Erbe today is in the center of Mantua, but once upon a time it belonged to the very first suburb of the virgilian city, whose oldest nucleus was located where Piazza Sordello is located. Its beauty is largely due to buildings raised or restored over the centuries, from the Middle Ages to the Renaissance and beyond. In particular, the Tower of the Clock was built in the year 1473 as a completion of the Palace of the Reason, where politics and justice were administered in the era before the Gonzaga family took power over Mantua. The author of the tower is Luca Fancelli, the Tuscan of Settignano who decided so much about the view of Mantua, carrying out the indications of Leon Battista Alberti. However, the imposing statue of the Immaculate Virgin Mary, the source of the Moon, the balcony and the upper crown, were added later. The XV century appearance of the tower and the square probably can be derived from an ornate wooden artwork of the Cathedral of Cremona, created by Giacomo Maria da Piadena called il Platino. Here stands out the stylized figure of the astronomical clock, invention of the genius of Bartolomeo Manfredi. He was first a mathematician, John’s of the Clock son. Astronomical clocks had spread mainly in Northern Europe already during the XIV century. In Italy, the oldest is certainly located in Padua, which today overlooks Piazza dei Signori but which came, at least as a conception, from the lost Reggia Carrarese. The astronomical clock of Mantua is the second built in Italy in order of time, and the first one that today we can see in the site for which it was conceived.