ABSTRACT
The scientific investigation of urban patterns being considered as a system is comparatively recent. The first, universally known analysis is that of the settlement system of southern Germany, published in 1933. The gradual crystallization of urban systems went hand in hand with the rise of states. Short-circuiting the feudal prerogatives, the royal rulers of Western European countries, being best protected against invasions, constantly attempted to enlarge their territories and to increase their power, taking on more and more agricultural trade surpluses. The first factor determining the distribution of towns is to be found in the speed of communication, which prevailed at the beginning of urban networks when the first urban 'crystallization' occurred. The second principle is that European towns and cities have been organized in systems, on a network basis, since the Middle Ages. The third principle relates to the dynamics of the original urban grid.
