The plan of Florence in 1427 shows a group of twenty unmistakable 'insulae', each of them about 1-1/8 acre in area, that is, very similar in size to the 'insulae' of Turin.

This group is bounded by the modern streets Tornabuoni on the west, Porta Rossa on the south, Calzaioli on the east, Teatina on the north; it covers a rectangle of some 305 x 327 yds., not quite 21 acres.
[81] On Roman and early mediaeval Florence see Villani, _Cronica_ (written about 1345, published 1845), i.

61, 89, 120; R.
Davidsohn, _Geschichte von Florenz_ and _Forschungen_ (Berlin, 1886); L.A.Milani, _Notizie degli Scavi_, 1887, p.

129; plan of the Centro in 1427 by Comm.

Guido Carocci, _Studi storici sul Centro di Firenze_ (Florence, 1889); _Monumenti antichi_, vi.