While the necessity of transporting articles from the East to supply the demand thus created in the West gave a stimulus to commerce and navigation, manufactures were encouraged and developed by the operation of the same cause. The Italians learned from the Greeks the art of weaving silk, which soon resulted in the weaving of cloth of gold and silver. They learned to mould glass in a multitude of new and curious forms. From the manufactories of Syria, where stuffs were made of camels' hair, improvements were introduced into the manufactures of Europe, where they were woven of no other material than lambs' wool. Palestine also suggested to crusaders returning home the advantages of windmills for grinding flour. Arabia furnished the art of tempering arms and polishing steel, of chasing gold and silver, of mounting stones in rich and massive settings. Constantinople furnished the Christians with many splendid specimens of ancient art,--groups, statues, and the Corinthian horses, and thus awakened European taste. Nearly all the Gothic monuments of Europe which still excite the admiration of the tourist owe their existence to this communication with the Greeks by means of the Crusades, and to the wonder which seized the Frank and Lombard at the sight of the churches and palaces of Byzantium. The Europeans carried back with them the architecture of the Saracens. Saint Mark's at Venice was built from the plans, and under the direction, of an unbeliever. The Cathedral and Spire of Strasburg, with their gigantic and yet delicate proportions, the Minster of Amiens, the Sainte Chapelle of Paris, were constructed in close imitation of the chef-d'oeuvres of Eastern art. Painting upon glass was also brought from Constantinople, and the early painters of Christendom were speedily employed in tracing in colors, upon the windows of abbeys and cathedrals, the exploits of the Crusaders and the triumphs of the Cross. From the Arabs and the Greeks, too, the Europeans received their first lessons in the natural and exact sciences. Imperfect and incomplete as were the astronomy, the botany, the mathematics, and the geography of the Arabians, they were far in advance of the same professions as understood and practised in Europe. The languages were improved and enriched by the association and exchange of ideas into which English, Germans, Italians, and French were forced. The confusion of tongues, which was as complete as at Babel, was somewhat corrected by the harmony of interest and oneness of purpose which animated all, of whatever name and lineage, who gathered around the Sepulchre.