Returning a ruined man, he married his daughter to the illegitimate son of Philip, a half-brother of Louis, a child of twelve; and as his guardians, the king and prince got possession of the castle. This castle was almost at the gates of Paris, and a standing menace to the communications of the kingdom: therefore their delight was great. "They rejoiced as though they had taken a straw from their eyes, or as though they had burst the barrier which imprisoned them."[149] And the old king said to his son: "Guard well the tower, Louis, which has aged me with chagrin, and through whose treachery and wicked fraud I have never known peace and quiet."[150]
Yet the destruction of the local nobility in Syria was the least important part of the social revolution wrought by the crusades, for though the power of the barons might have thus been temporarily broken, they could never have been reduced to impotence unless wealth had grown equal to organizing an overwhelming attack. The accumulation of wealth followed the opening of the Eastern trade, and its first effect was to cause the incorporation of the communes.
Prior to 1095 but one town is known to have been chartered, Saint Quentin, the capital of Vermandois, about 1080,[151] but after the opening of the Syrian ports the whole complexion of society changed. Noyon was chartered in 1108, Laon in 1111, Amiens in 1113, and then free boroughs sprang up on every side.
For want of the mariner's compass, commerce could not pass north by the Straits of Gibraltar. Merchandise had therefore to go by land, and exchanges between the north and south of Europe centred in the County of Champagne, whose fairs became the great market of the thirteenth century.
The earliest dated document relating to these fairs is a deed drawn in 1114 by Hugh, Count of Troyes, by which he conveyed certain revenues derived from them to the Abbey of Montier-en-Der. Fifty years later, such mentions had grown frequent, and by the year 1200 the fairs had attained their full development.[152]
Weaving had been an industry in Flanders under the Romans, and in the time of Charlemagne the cloth of the Low Countries had been famous; but in the twelfth century the manufacture spread into the adjoining provinces of France, and woollen became the most valuable European export. The fleeces were brought chiefly from England, the weaving was done on the Continent, and one of the sources of the Florentine wealth was the dressing and dyeing of these fabrics to prepare them for the Asiatic market.