SIGNIA (mod. Segni), an ancient town of Latium (adiectum), Italy, on a projecting lower summit of the Volscian mountains, above the Via Latina, some 35 m. S.E. of Rome. The modern railway station, 33 m. S.E. of Rome, lies 5 m. S.E. of Signia, 669 ft. above sea level. The modern town (2192 ft.) occupies the lower part of the ancient site. Pop. (1901) 6942. Its foundation as a Roman colony is ascribed to Tarquinius Superbus, and new colonists were sent there in 495 B.C. Its position was certainly of great importance: it commands a splendid view, and with Anagnia, which lies opposite to it, guarded the approach to the valley of the Trerus or Tolerus (Sacco) and so the road to the south. It remained faithful to Rome both in the Latin and in the Hannibalic wars, and served as a place of detention for the Carthaginian hostages during the latter. It seems to have remained a place of some importance. Like Cora it retained the right of coining in silver. The wonderfully hard, strong cement, made partly of broken pieces of pottery, which served as the lining for Roman water cisterns (opus signinum) owes its name to its invention here (Vitruvius, viii. 7, 14). Its wine, pears and charcoal were famous in Roman times. In 90 B.C. it became a municipium with a senalus and praetores. In the civil war it joined the democratic party, and it was from here that in 82 B.C. Marius marched to Sacriportus (probably marked by the medieval castle of Piombinara, near Segni station, commanding the junction of the Via Labicana and the Via Latina; see T. Ashby, Papers of the British School at Rome, London, 1902, i. 125 sqq.), where he was defeated with loss. After this we hear no more of Signia until, in the middle ages, it became a papal fortress.
The city wall, constructed of polygonal blocks of the mountain limestone and ij m. in circumference, is still well preserved and has several gates; the largest, Porta Saracinesca, is roofed by the gradual inclination of the sides until they are close enough to allow of the placing of a lintel. The other gates are mostly narrow posterns covered with flat monolithic lintels, and the careful jointing of the blocks of which some of them are composed may be noted. Their date need not be so early as is generally believed (cf. NORBA) and they are certainly not pre-Roman. A portion of the wall in the modern town has been restored in opus quadratum of tufa in Roman times. Above the modern town, on the highest point, is the church of S. Pietro, occupying the central cella of the ancient Capitolium of Signia (which had three cellae). The walls consist of rectangular blocks of tufa, and the whole rests upon a platform of polygonal masses of limestone (see R. Delbriick, Das Capitolium von Signia, Rome, 1903). An open circular cistern in front of the church lined with rectangular blocks of tufa may also be noted. (T. As.)
Note - this article incorporates content from Encyclopaedia Britannica, Eleventh Edition, (1910-1911)