Early Middle Ages
In the 5th century A.D. Volterra became the diocese of a vast area corresponding to that of the Etruscan Lucomon and Roman Municipium and a small temple dedicated to Mary, the first duomo of the city , was erected. Giusto was the first bishop and patron of Volterra and is said to have miraculously saved the city in the 6th century. The legend tells the story of how Giusto encouraged the populace , exhausted by famine, to throw bread over the defensive walls; grateful for the gift or simply convinced that the city was capable of resisting a long siege the Barbarians withdrew and the city was saved. The following years were governed by the Lombards and Franks. During the 9th and 10th centuries,due to the discretionary investiture conceded them by the Emperors, the Signoria of the Volterran bishops rose to power governing the city and the neighbouring cities within the diocese.
Growing prosperity not only enhanced the religious life but also the social, economic and jurisdictional life of the city ; Four markets and just as many religious feast days were conceded in the 9th century by the Carolingian emperors -an important concession for the markets were exempt from taxes and marked a recovery of trade in the Volterran territory.

The free Commune
and the Bishop-Counts
After the last Hungarian invasion and the feud between Berengario I and Alberto Marquis of Tuscany which almost brought Volterra to ruin, the increase in population (after the year thousand) encouraged the formation of the first medieval quarters of the city which were mostly concentrated around the area of Castello: Borgo di Santa Maria ( today Via Riccirelli), Borgo dell’abate (today Via Buonparenti and Via Sarti), one perpendicular and the other parallel to the Castello walls.
The 12th century was marked by the violent conflicts between the nobility and the bishop’s rule which was to reach a climax in1150 when Galgano dei Pannocchieschi became bishop.
The feudal lords and the middle classes united against the bishops and the Palazzo dei Priori was begun in 12O8 and completed in 1257 ,as a symbol of the free commune . The newly formed commune purchased rights on the extraction of salt (the city’s main income),sulphur, vetriol and alum in the areas of Larderello, Sasso and Libbiano but soon found itself struggling for independence against the expansions of Pisa,Siena and Florence.
Many house towers including the Tower of the Little Pig were erected as fortifications to defend the noble families from their frequent and bitter fights for power. The Medieval defensive wall was built to much expense to enclose a residential area inhabited by a few thousand people and the cathedral façade was also embellished in1254.

The war with Florence
Volterra was also involved in the factional struggles between the Guelfs and Gibellines hence the feud between the Belforti and Allegretti families contesting for control of the commune.
Ottaviano Belforti constituted a Signoria at the beginning of the 14th century succeeded by his son Bocchino who in a desperate attempt to retain power began negotiations to sell the city to Pisa.
The city revolted and Bochino was decapitated. Upon his death in 1361 and the definite expulsion of the Belforti , the city fell prey to Florentine rule and although independence was formally conceded,government autonomy was strongly limited and Florence had also extended the new land taxes to Volterra clearly indicating that Volterra was now subject to Florence.The Volterrans resolutely contended the measure and Giusto Landini who led the revolt, lost his life antagonist to the hegomonic politics of Florence.
Volterra was finally subjected to Florence in 1472 following a controversy over the alum deposits discovered in the area two years earlier. Lorenzo dei Medici welcomed the occasion to intervene and Volterra was sacked with appalling violence by the troups led by the Duke of Montefeltro
The fortress on the Piano di Castello was ordered by Lorenzo the Magnificent in 1472 to control the city and the Siena territory and became a symbol of Florentine rule.

Palazzo dei Priori