Clusium (Ancient Greek: Κλύσιον, Klýsion, or Κλούσιον, Kloúsion; Umbrian: Camars) was an ancient city in Italy, one of several found at the same site overlapping the current municipality of Chiusi (Tuscany). The Roman city remodeled an earlier Etruscan city, Clevsin, found in the territory of a prehistoric culture, possibly also Etruscan or proto-Etruscan. The site is located in northern central Italy on the west side of the Apennines.
Lars Porsena (or Porsenna; Etruscan: Pursenas) was an Etruscan king (lar) known for his war against the city of Rome. He ruled over the city of Clusium (Etruscan: Clevsin; modern Chiusi). There are no established dates for his rule, but Roman sources often place the war at around 508 BC.
The Via Cassia (lit. 'Way of Cassius') was an important Roman road striking out of the Via Flaminia near the Milvian Bridge in the immediate vicinity of Rome and, passing not far from Veii, traversed Etruria. The Via Cassia passed through Baccanae, Sutrium, Volsinii, Clusium, Arretium, Florentia, Pistoria, and Luca, joining the Via Aurelia at Luna.
The Via Cassia intersected other important roads. At mile 11 the Via Clodia diverged north-north-west. At Sette Vene, another road, probably the Via Annia, branched off to Falerii. In Sutrium, the Via Ciminia split off and later rejoined.
Publius Horatius Cocles was an officer in the army of the early Roman Republic who famously defended the Pons Sublicius from the invading army of Etruscan King Lars Porsena of Clusium in the late 6th century BC, during the war between Rome and Clusium. By defending the narrow end of the bridge, he and his companions were able to hold off the attacking army long enough to allow other Romans to destroy the bridge behind him, blocking the Etruscans' advance and saving the city.
Volsinii or Vulsinii (Etruscan: Velzna or Velusna; Greek: Ouolsinioi, Ὀυολσίνιοι; Ὀυολσίνιον), is the name of two ancient cities of Etruria, one situated on the shore of Lacus Volsiniensis (modern Lago di Bolsena), and the other on the Via Clodia, between Clusium (Chiusi) and Forum Cassii (Vetralla). The latter was Etruscan and was destroyed by the Romans in 264 BC following an attempted revolt by its slaves, while the former was founded by the Romans using the remainder of the Etruscan population rescued from the razed city.
Modern Bolsena, Italy, in the region of Lazio, descends from the Roman city. The location of the Etruscan city is debated. Umbrian Orvieto, about 14 km (8.7 mi) from Bolsena, is a strong candidate.