Fortezza di San Martino

Above San Piero a Sieve, the Fortezza di San Martino covers a hilltop with nine bastions, two gates and a pentagonal keep. Construction began in 1569 at the command of Cosimo I de’ Medici; Bernardo Buontalenti later gave the fortress its definitive arrangement.

Why it matters

Cosimo I commissioned the fortress to guard the northern approaches to Florence and the Medici state’s possessions. Its extensive circuit and nine bastions reflect the strategic importance of the Mugello. The fortress later became obsolete for military use and its enclosed spaces were adapted for civilian purposes. The Lab Fortezza Abitata project now gathers memories of life within its walls.

What to notice

The fortress has an irregular, nearly rectangular plan, reinforced by nine broad bastions. Porta Fiorentina faces south towards Florence and Porta Bolognese north towards the Apennine roads. At the highest point, a pentagonal mastio forms a smaller fortified keep. Within the perimeter, the garrison once had windmills, barracks, powder stores, cisterns, cannon workshops and a chapel.

Context and history

Construction began on 30 June 1569. The work continued for decades: the Comune credits Bernardo Buontalenti with completing the definitive arrangement, probably in the last decade of the sixteenth century, while Visit Tuscany places completion in the early seventeenth century under Ferdinando I. The fortress was demilitarised in 1774 under Pietro Leopoldo. Its enclosed land later supported farming, and during the Second World War it sheltered refugees. The Lab Fortezza Abitata project documents this later history through photographs, maps and interviews.