surrender in 774 to Charlemagne. At this point, the city was inundated with a swarm of Frankish overseers who married into the existing Sienese nobility and left a legacy that can be seen in the abbeys they founded throughout Sienese territory. Feudal power waned however, and by the death of Countess Matilda in 1115 the border territory of the Mark of Tuscia which had been under the control of her family, the Canossa, broke up into several autonomous regions.
Siena prospered as a city-state, becoming a major centre of money lending and an important player in the wool trade. It was governed at first directly by its bishop, but episcopal power declined during the 12th century. The bishop was forced to concede a greater say in the running of the city to the nobility in exchange for their help during a territorial dispute with Arezzo, and this started a process which culminated in 1167 when the commune of Siena declared its independence from episcopal control. By 1179, it had a written constitution.
During the early 13th century that the majority of the construction of the Siena Cathedral (Duomo) was completed. During the same period the Piazza del Campo grew in importance as the centre of secular life. New streets were constructed leading to it, and it served as the site of the market and the location of various sporting events (perhaps better thought of as riots, in the fashion of the Florentine football matches that are still practised to this day). A wall was constructed in 1194 at the current site of the Palazzo Pubblico to stop soil erosion, an indication of how important the area was becoming as a civic space
In the early 12th century a self-governing commune replaced the earlier aristocratic government. The consuls who governed the republic slowly became more inclusive of the poblani, or common people, and the commune increased its territory as the surrounding feudal nobles in their fortified castles submitted to the urban power. Siena's
