 Its length from east to west is accurately determined by the fact that the "Via Appia", which runs from north-west to south-east from Casilinum to Calatia, turns due east very soon after passing the so-called "Arch of Hadrian" (a triumphal arch of brickwork, once faced with marble, with three openings, erected in honour of some emperor unknown), and continues to run in this direction for (6,000 ancient Oscan feet).The west gate was the "Porta Romana"; remains of the east gate (the name of which we do not know) have been found.This fact shows that the main street of the town was perfectly oriented, and that before the "Via Appia" was constructed, i.e.