The Lago di Bracciano is a lake in Southern Etruria with a surface of 57.5 square kilometers. Its maximum length is 9.3 kilometers. The width goes up to 8.7 kilometers. The extent of the lake is 31.5 kilometers. Its water originates in part from some small rivers, and in part from underground springs. The lake is situated in a volcanic area, a fact which is important in our case.
The Romans called the Lago di Bracciano lacus Sabatinus. We find the lake referred to by this name on the tabula Peutingeriana. Collumella mentions the lake in his work De re rustica in the chapter on pisciculture. He points out that due to farmers' care some lakes have sea-fish, which can stand fresh water:
Inde Velinus, inde etiam Sabatinus, item Volsiniensis et Ciminius lupos auratasque procreaverunt, ac si qua sunt alia piscium genera dulcis undae tolerantia.