If the chess-board fashion becomes now, with seeming suddenness, the common--although not the universal--rule, that is probably the outcome of the developments sketched in the last chapter.
Approximations to chess-board planning had been here and there employed in the century before Alexander.

When his conquests and their complicated sequel led, amongst other results, to the foundation of many new towns, it was natural that the most definite form of planning should be chosen for general use.
We might, however, wonder whether its adoption was helped by the military character of the generals who founded, and the discharged soldiers who formed the first inhabitants of so many among these towns.

Military men are seldom averse to rigidity.

It is worth noting, in this connexion, that when chess-board planning came into common use in the Roman Empire, many--perhaps most--of the towns to which it was applied were 'coloniae' manned by time-expired soldiers.

So, too, in the Middle Ages and even in comparatively modern times, the towns laid out with rectangular street-plans in northern Italy, in Provence, in the Rhine Valley, are for the most part due in some way or other to military needs.[23] In our own days rectangular planning is a dominant feature of the largest and newest industrial towns.