Though walls, gates, temples, baths, palaces, amphitheatres still stand stubbornly erect amidst a flood of modern dwellings, they are but the islands which mark a submerged area.

The paths and passages by which men once moved across that area have vanished beneath the waves and cannot be recovered from any survey of these visible fragments.

There is hardly one modern town in all the European and African provinces of the Roman Empire which still uses any considerable part of its ancient street-plan.

In our own country there is no single case.

In Gaul and Germany, two or three streets in Cologne and one or two in Trier are the sole survivals.[87] In Illyricum there is no example unless possibly at Belgrade.