We start from the municipality of Sinalunga and go past some ancient castles that once belonged to the Cacciaconti, scions of the Scialenga counts, before they passed to the Republic of Siena or other noble families. The entrance to the valley starts along the Foenna, one of the streams that was crucial in the reclamation of the marshland, near Rigomango. The name of this hilltop castle actually derives from this stream, which was considered a rigum magnum (an important watercourse), near which the original settlement was founded on the floodplain. Our route continues towards Farnetella, which according to Bartolomeo Gherardini, auditor general to an earlier Grand Duke, was in 1676 "located on a hill with good air, its walls mostly in ruins. It has two gates and three small streets". The next leg of the Leopoldian tour takes us to the medieval village of Sinalunga, originally Asinalonga (Ad Sinus Longus, which means 'in the direction of a long inlet', the inlet in question having been grooved out by the Foenna. The lower part of the town is called Pieve, and not without reason: the Peutinger Table shows the Parish Church (Pieve in Italian) of San Pietro ad Mensulas, which stands on the Via Cassia between Clusio (now Chiusi) and Sena Julia (Siena).