Left: The fortified hill. Right: The bastion defending the Florentine gate.

The S.Martino fortress stands on the top of a hill, from here it dominates the underlying town of S.Piero a Sieve and great part of the 'Mugello' (the part of northeast Tuscany between Florence and the Apennines). Its construction was ordered by Cosimo I de' Medici to create a stronghold for the defense of the Florentine territory under pressure of the local population, often subjected to depredations perpetuated by armies and outlaw gangs coming from the north.

Responsible of the project was one of the greatest architects of that time: Baldassarre Lanci, the man responsible for the fortifications of Grosseto, Siena and Radicofani. The construction began the 30th of June 1569. Two years later Lanci died and Bernardo Buontalenti took his place. Beacuse of the greatness of the works, the fortress was completed only in the year 1608, under the reign of Ferdinand I. S.Martino its considered the most extensive Italian fortifications of all times.

In practice S.Martino its an entire fortified mountain, with the ramparts perfectly adapted to the terrain. The fortress has an irregular plan, similar to a rectangular, reinforced with nine bastions and two gates: the 'Florentine' to south and the 'Bolognese' at north. At the interior of the mammouth walled curtain, constituted of high inclined brick walls, rises the so called 'keep', as a matter of fact a smaller fortress with five sides of bastionated walls.

This inner fortress is positioned near the Florentine gate. Inside there were also wind mills, barracks, arms and munitions deposits, cisterns, workshops for the construction and reparation of fire arms and a chapel.

Looking at this fortress it's easy to do a comparison with the Poggio Imperiale Fortress of Poggibonsi. The difference is that at S.Martino we don't find a completely fortified city but an exclusively military complex able to contain an entire army! Restored after the earthquake of 1762 the fortress was dismantled in 1784 following the order of Leopoldo I, because at that time the menace of invasion from the north ended. The barracks became farmhouses for the peasants of the area. The walled circuit remained unmaintained until the present.

The greatest Italian fortification of the Renaissance lies abandoned, like a dying giant lying down on the hill. The actual good state of conservation is granted to the high quality of the construction and not by human interventions; the fortress is visible only from the outside.