The first references of this ancient route date back to the 9th century (AD) and referred to a stretch of road in the province of Siena as reported by an ancient parchment dating back to 876 and preserved in the Abbey of San Salvatore on Monte Amiata. Although in reality, to have the first description of the route known as Via Francigena we will have to wait until the end of the 10th century, when the Bishop Sigerico of Canterbury returning from Rome to receive the pallium papal, marked the route completed that brought him back to Canterbury from Rome. The passage of the Via Francigena in the Middle Ages, a road structure that connected Italy with Europe and vice versa, favored the repopulation and development of many communities, as also happened in the Valdelsana area. The route of the Francigena described by Archbishop Sigeric probably entered the municipal area of Colle not too far from Campiglia dei Fosci, as evidenced by the Church of San Bartolomeo. Through an approximately reconstructable route, he then had to continue to Boscona where there is another Romanesque church dedicated to San Michele and then head towards Pieve d’Elsa already mentioned by Sigerico. Right at the height of the Pieve, which no longer exists, a dirt road leads to the baths of San Marziale or Caldane, old baths known by Etruscans and Romans.