Special circumstances or special men have called it into brief activity.

The 'bastides' and the 'villes neuves' of thirteenth-century France were founded at a particular period and under special circumstances, and, brief as the period was and governed by military urgencies, they were laid out on a more or less definite plan (p.

143).

The streets designed by Wood at Bath about 1735, by Craig at Edinburgh about 1770, by Grainger at Newcastle about 1835, show what individual genius could do at favourable moments.

But such instances, however interesting in themselves, are obviously less important than the larger manifestations of town-planning in Greece and Rome.
In almost all cases, the frequent establishment of towns has been accompanied by the adoption of a definite principle of town-planning, and throughout the principle has been essentially the same.