But the limits indicated above give the not unsuitable dimensions of 46 acres (380 x 590 yds.), while the history of the twenty indubitable insulae of the Centro remains full of interest.

We see here, as clearly as anywhere in the Roman world, how the regular Roman plan has gradually been distorted by encroachments and how, even in its irregularity, it has had power to drive modern builders towards its ancient fashion.
Of the interior of the Roman town little is known.

The streets now called Strozzi and Speziali plainly preserve the Roman main street from east to west, while the Via Calimara overlies that which ran from north to south.

Where these crossed was the mediaeval Mercato Vecchio, now enlarged into a patriotic Piazza Vittorio Emmanuele; here we may put the Roman forum, and here too, by the former church of S.Maria in Campidoglio, was the temple of Capitoline Juppiter.

There were also theatres, a shrine of Isis, and, outside the Roman limit, an amphitheatre still discernible in the curves of certain streets (plan 17 B).