The palaces of Medici power

Also known as the Fortress of St. John the Baptist, the fortification of the city walls (originally Castello Alessandria) was built by the architect Pier Francesco da Viterbo and Antonio da Sangallo the Younger between 1534 and 1537 by order of Alessandro De’ Medici. 

The fortress is pentagonal in shape and was built hastily, at the great financial expense, to ensure the Medici controlled the city after they had just returned there with the support of Charles V of Habsburg (Siege of Florence 1529 – 1530). In addition, it would serve to provide accommodation for a strong contingent of troops and as a refuge for the rulers in the event of a revolt, as well as to impress and intimidate the Florentines, hence the monumental appearance that Antonio da Sangallo gave the side facing the city.

The fortress maintained its military role even in the modern era when the officers’ palace and a small theatre were added. Today, after undergoing restoration, which has brought to light the 14th-century Porta Faenza, it is home to exhibitions and the Opificio Delle Pietre Dure with numerous scientific and restoration laboratories. Still, it is possible to visit the interior of the Mastio. Here, the octagonal hall, with a great herringbone brick vault, was part of the monumental access route to the fortress, and some other structures, such as the powder magazine.

The fortress, unlike what was conventional at the time of its construction, does not have a regular plan with fully developed bastions identical to each other and equipped with earwalls. The irregular pentagonal plan to graft onto the previous walls was built in the late 13th – early 14th century by the architect Arnoldo di Cambio, to whom Vasari attributes the construction of the churches of Santa Croce and Santa Maria Novella as well as the Palazzo Della Signoria. 

In the centre of the longest side, the keep was built, a platform-like structure encompassing the ancient Porta Faenza, forming a mini-bastion that allows artillery fire.

The curtain wall and bastions are made of brick, which is cheaper and more suitable for absorbing artillery fire. At the same time, the keep was built of “pietra forte”, a fine-grained sandstone typical of Florentine construction. The walls were carved with a decorative motif of balls, alluding to the Medici coat of arms, and diamonds, decorative motifs characteristic of the Renaissance even if unusual on a military construction scale. 

With this latest example of Medici construction, we can meditate on the power and influence this family brought not only to Florence but to the entire European scene. More specifically, their refinement and strong artistic influence brought about significant changes in the Renaissance. Thanks to the De Medici, today we inherit these wonderful gems that still stand in memory of the incredible talents that converged in Florence under the Medici call.