At the peak of Rome's development, no fewer than 29 great military highways radiated from the capital, and the late Empire's 113 provinces were interconnected by 372 great roads. The whole comprised more than 400,000 kilometres (250,000 miles) of roads, of which over 80,500 kilometres (50,000 mi) were stone-paved. In Gaul alone, no less than 21,000 kilometres (13,000 mi) of roadways are said to have been improved, and in Britain at least 4,000 kilometres (2,500 mi). The courses (and sometimes the surfaces) of many Roman roads survived for millennia; some are overlaid by modern roads.
Dionysius of Halicarnassus, Ant. Rom. 3.67.5
Livy mentions some of the most familiar roads near Rome, and the milestones on them, at times long before the first paved road—the Appian Way. Unless these allusions are just simple anachronisms, the roads referred to were probably at the time little more than levelled earthen tracks. Thus, the Via Gabina (during the time of Porsena) is mentioned in about 500 BC; the Via Latina (during the time of Coriolanus) in about 490 BC; the Via Nomentana (also known as "Via Ficulensis"), in 449 BC; the Via Labicana in 421 BC; and the Via Salaria in 361 BC.
"With the exception of some outlying portions, such as Britain north of the Wall, Dacia, and certain provinces east of the Euphrates, the whole Empire was penetrated by these itinera (plural of iter). There is hardly a district to which we might expect a Roman official to be sent, on service either civil or military, where we do not find roads. They reach the Wall in Britain; run along the Rhine, the Danube, and the Euphrates; and cover, as with a network, the interior provinces of the Empire."