True that no new principle was illustrated by any of these discoveries, as Whewell said; but medieval science had done something more than the actual discovery of new principles.  It had prepared the discovery of all the new principles which we know at the present time in mechanical sciences:  it had accustomed the explorer to observe facts and to reason from them.  It was inductive science, even though it had not yet fully grasped the importance and the powers of induction; and it laid the foundations of both mechanics and natural philosophy.  Francis Bacon, Galileo, and Copernicus were the direct descendants of a Roger Bacon and a Michael Scot, as the steam engine was a direct product of the researches carried on in the Italian universities on the weight of the atmosphere, and of the mathematical and technical learning which characterized Nuremberg.

But why should one take trouble to insist upon the advance of science and art in the medieval city?  Is it not enough to point to the cathedrals in the domain of skill, and to the Italian language and the poem of Dante in the domain of thought, to give at once the measure of what the medieval city created during the four centuries it lived?

The medieval cities have undoubtedly rendered an immense service to European civilization.  They have prevented it from being drifted into the theocracies and despotical states of old; they have endowed it with the variety, the self-reliance, the force of initiative, and the immense intellectual and material energies it now possesses, which are the best pledge for its being able to resist any new invasion of the East.  But why did these centres of civilization, which attempted to answer to deeply-seated needs of human nature, and were so full of life, not live further on?  Why were they seized with senile debility in the sixteenth century? and, after having repulsed so many assaults from without, and only borrowed new vigour from their interior struggles, why did they finally succumb to both?

Various causes contributed to this effect, some of them having their roots in the remote past, while others originated in the mistakes committed by the cities themselves.  Towards the end of the fifteenth century, mighty States, reconstructed on the old Roman pattern, were already coming into existence.  In each country and each region some feudal lord, more cunning, more given to hoarding, and often less scrupulous than his neighbours, had succeeded in appropriating to himself richer personal domains, more peasants on his lands, more knights in his following, more treasures in his chest.  He had chosen for his seat a group of happily-situated villages, not yet trained into free municipal life—­Paris, Madrid, or Moscow—­and with the labour of his serfs he had made of them royal fortified cities, whereto he attracted war companions by a free distribution of villages, and merchants by the protection he offered to trade.  The germ of a future State, which began