On the road north to Siena is the remarkable ruins of the Abbey of San Galgano, named after a medieval knight who chose to live as a hermit, and whose sword is buried deep in a large stone in a chapel beside the monastery, suggested as one of the origins of the legend of King Arthur.

The extraordinary Gothic church was built in the 13th century, thrived for a century as magistrates of the Kingdom of Siena, but was repeatedly sacked by bandits and soon abandoned, with only a single, solitary abbot remaining in the ruins for hundreds of years. In 1786 the roof collapsed, the bell tower was destroyed by lightning, and the abbot fled, leaving only the skeleton of the beautiful ornate walls remaining.