During this period, European cities had no paving or lighting, and one could not step from a doorway in London or Paris without plunging ankle deep in mud. They had practically no drainage and they were, at frequent intervals devastated by the plague. But the cities of Andalusia, built and governed by the Moors in Spain, were drained, well lighted and solidly paved. They had public libraries and public schools. From their medical colleges Europe obtained the only doctors it had. In the cities of Christian Europe these enlightened people were treated like dogs, while in their wonderful cities, visiting Christians were met with a hospitality and broad toleration wholly exceptional in the middle ages. In Europe, even toward the close of this period, broad, scientific thinking was impossible. Nicholas Copernicus, in the 16th century, afraid of the faggot, carried as a secret locked in his own bosom, that heliocentric theory which is the foundation of modern astronomy. His great disciple Giordano Bruno, for expounding that theory with rare ability, after it was revealed by the great Prussian, was hunted through Europe like a wild animal and finally burned at the stake. For the same reason, the third person in the trinity of the 16th century’s greatest thinkers, Galileo, was harassed and humiliated, and at last died a prisoner in his own house. But all through this period, despite its intellectual stagnation, economic evolution proceeded, laying the foundation for a new intellectual superstructure. That evolution manifested itself chiefly in the rise and growth of a trading class. To the existence of such a class in its society, the Arabians owed their greater liberality, and scientific spirit. When Vasca Da Gama sailed down the west coast of Africa and around the Cape of Good Hope into the Indian Ocean, trusting to chance for the outcome of his voyage, he found the Arabians directing their vessels by a strange instrument which we now call the mariner’s compass. The merchants of Genoa and of Spain discovered that orthodox superstitions did not help but did seriously injure, their commerce. As captains for their ships they preferred for purely economic reasons, men who had become infected with the ideas of navigation of the pagan Arabians, to men who took their ideas of the universe from the city bishop or the village priest and kept their ships close to land, afraid lest they should sail off the edge of the world, or into that great hole where the angels put the sun at night, after they had finished rolling it across the sky. It was the growth and final triumph of this trading class, with economic interests and a mode of wealth production that demanded the liberation of science, that abolished the thumbscrew and the stake. Voltaire, Rousseau, and the encyclopaedists were obnoxious to the feudal regime, lay and clerical, because they were the prophets and mouthpieces of the rising bourgeoisie.