CASSIA, VIA, an ancient high-road of Italy, leading from Rome through Etruria to Florentia (Florence); at the 11th mile the Via Clodia (see Clodia, Via) diverged north-north-west, while the Via Cassia ran to the east of the Lacus Sabatinus and then through the place now called Sette Vene, where a road, probably the Via Annia, branched off to Falerii, through Sutrium (where the Via Ciminia, running along the east edge of the Lacus Ciminius, diverged from it, to rejoin it at Aquae Passeris, north of the modern Viterbo  ), Forum Cassii, Volsinii, Clusium and Arretium, its line being closely followed by the modern highroad from Rome to Florence. The date of its construction is uncertain: it cannot have been earlier than 187 b.c.,  when the consul C. Flaminius constructed a road from Bononia to Arretium (which must have coincided with the portion of the later Via Cassia). It is not, it is true, mentioned by any ancient authorities before the time of Cicero, who in 45 b.c. speaks of the existence of three roads from Rome to Mutina, the Flaminia, the Aurelia and the Cassia. A milestone of a.d. 124 mentions repairs to the road made by Hadrian from the boundary of the territory of Clusium to Florence, a distance of 86 m.
See Ch. Hülsen in Pauly-Wissowa, Realencyclopadie, iii. 1669.
 The Via Traiana Nova, or the (viae) tres Traianae, mentioned in inscriptions with the Cassia and Clodia as under the same curator, are not certainly identifiable.
 Having regard to the military importance of Arretium during the Punic wars, it is difficult to believe that no direct road existed to this point before 187 b.c.
Note - this article incorporates content from Encyclopaedia Britannica, Eleventh Edition, (1910-1911)