People came together in cities in order to live. They remain together in order to live the good life. (Aristotle)
From ancient times until the latter half of the twentieth century, cities were indisputably the very essence of civilisation, although Aristotle's reason for their continuing existence was clearly not the only one. They probably came into being in the first place when interdependent craftsmen found that they could better serve their separate agricultural villages by working together in a central location. But they eventually became centres of power capable of defending themselves and exercising power over their rivals. In medieval Europe they became oases of semi-freedom within the feudal system.
In England, feudalism was actually brought to an end by London's support for the barons against the King in 1215; and it is ironic that the comparatively stable form of government that followed Magna Carta made strongly defended towns no longer necessary. This reduced the power of English towns in comparison with the city states of mainland Europe; but it allowed them to expand beyond their defensive walls, while their European rivals were constrained by their fortifications. Thus Paris, which remained a fortified city until 1870, had twice the population density of London-and still does! (Mogridge, 1985).
If fortifications were no longer a curb on the expansion of English towns, the distances that people could walk, or goods could be carried, ultimately were. It was not until the 1860s that the railways started carrying people to work rather than just carrying fuel and raw materials to urban factories at the centres of population. However, as soon as it did become possible to live remote from one's place of work in the smoky city, the better off were quick to do so. In London the Great Northern Railway advertisements posed the question 'Why