Gradually, however, there arose in the aristocratically organized middle age a new power. This was the trading and manufacturing classes. As soon as the feudal nobility gave any measure of security, and much more extensively when kings grew strong enough to stretch the royal power over their turbulent feudatories, the irrepressible trading instinct asserted itself. English wool found its way to Flanders, French wine to England, the silks and spices and gems of the East to Europe. Busy and wealthy cities sprang up in districts favorable for manufacture and along the great trade routes between East and West. Kings, eager to assert their sovereignty over the anarchic barons, allied themselves with this new burgher class, which was on its part glad to support a power that promised it deliverance from such very imperfect and costly protectors as the feudal lords had shown themselves to be. The Crusades, especially, stimulated trade and in the nearly two centuries (A.D. 1096-1270) during which the crusading spirit was active, the most notable feature of the social evolution of Europe was the rise of the towns. The rise of the towns meant the liberation of the people. No buildings in Europe have more sacred associations than the old city halls of the medieval cities of the Low Countries, France, and Germany. They were the birth place of modern freedom. Trade loves freedom and abhors all restrictions except such as are sometimes short-sightedly imposed by itself. The towns, wearied of the exactions of their castellated tyrants, won their freedom by purchase or by fighting, or co-operated with the king in reducing the barons to some measure of good behavior. During the last five hundred years, and especially since the Industrial Revolution effected by the use of machinery, the merchant and manufacturing classes have been steadily climbing into power. They have superseded or absorbed the pre-existing aristocracy. The old families have died out or been transformed by a profitable and strengthening admixture of rich plebeians. The bulk of even such an imposing aristocracy as that of Britain is composed of creations of the last two or three generations, and these so largely from the ranks of wealthy brewers that there is truth as well as wit in the saying that the British peerage is the British beerage. The sale of titles at the price of large contributions to political funds is admitted and defended. Even in Great Britain, with its impressive array of ancient names, aristrocracy has been largely converted into plutocracy. In a constitutionally democratic nation like the United States there is no other aristocracy.