Polybius, writing somewhere about B.C.
150, described in well-known chapters the scheme of the Roman camp, and he concludes much as follows: 'This being so, the whole outline of the camp may be summed up as right-angled and four-sided and equal-sided, while the details of its street-planning and its general arrangement are precisely parallel to those of a city' (VI.

31, 10).
He was comparing the Greek town, as he knew it in his own country, with the encampment of the Roman army; he found in the town the aptest and simplest parallel which he could put before his readers.

A much later writer, living in a very different environment and concerned with a very different subject, fell nevertheless under the influence of the same ideas.

Despite his 'sombre scorn' for things Greek and Roman, St.John, when he wished to figure the Holy City Jerusalem, centre of the New Heaven and New Earth, pictured it as a city lying foursquare, the length as large as the breadth, and entered by twelve gates, 'on the east three gates, on the north three gates, on the south three gates, and on the west three gates.'[41] [41] Revelation xxi.

13, 16.