The existence of a town-plan was first noticed by J.de Fontenay, _Bulletin monumental_, 1852, p.
365, but his map appears to be incorrect and his views generally are based too much on _a priori_ assumptions.
_Trier_ (fig.

30).
We may take another example from a northern city, Trier on the Mosel, in north-eastern Gaul (Augusta Treverorum).

It was in its later days a large city, perhaps the largest Roman city in western Europe.

When its walls were built and its famous north gate, the Porta Nigra, was erected, probably towards the end of the third century, they included a space of 704 acres, twenty-five times as much as the original Timgad, though, it must be added, this area may not have been wholly covered with houses.

But it was then an old city.