But they had reason for feelings of deeper gratitude in the substantial benefits which the favor of Charles secured to them. It was for Flemings that the highest posts even in Spain were reserved, and the marked preference thus shown by the emperor to his countrymen was one great source of the troubles in Castile. The soldiers of the Netherlands accompanied Charles on his military expeditions, and their cavalry had the reputation of being the best appointed and best disciplined in the imperial army. The vast extent of his possessions, spreading over every quarter of the globe, offered a boundless range for the commerce of the Netherlands, which was everywhere admitted on the most favorable footing. Notwithstanding his occasional acts of violence and extortion, Charles was too sagacious not to foster the material interests of a country which contributed so essentially to his own resources. Under his protecting policy, the industry and ingenuity of the Flemings found ample scope in the various departments of husbandry, manufactures, and trade. The country was as thickly studded with large towns as other countries were with villages. In the middle of the sixteenth century it was computed to contain above three hundred and fifty cities, and more than six thousand three hundred towns of a smaller size.[372] These towns were not the resort of monks and mendicants, as in other parts of the Continent, but they swarmed with a busy, laborious population. No man ate the bread of idleness in the Netherlands. At the period with which we are occupied Ghent counted 70,000 inhabitants, Brussels 75,000, and Antwerp 100,000. This was at a period when London itself contained but 150,000.[373] The country, fertilized by its countless canals and sluices, exhibited everywhere that minute and patient cultivation which distinguishes it at the present day, but which in the middle of the sixteenth century had no parallel but in the lands tilled by the Moorish inhabitants of the south of Spain. The ingenious spirit of the people was shown in their dexterity in the mechanical arts, and in the talent for invention which seems to be characteristic of a people accustomed from infancy to the unfettered exercise of their faculties. The processes for simplifying labor were carried so far, that children, as we are assured, began, at four or five years of age, to earn a livelihood.[374] Each of the principal cities became noted for its excellence in some branch or other of manufacture. Lille was known for its woollen cloths, Brussels for its tapestry and carpets, Valenciennes for its camlets, while the towns of Holland and Zealand furnished a simpler staple in the form of cheese, butter, and salted fish.[375] These various commodities were exhibited at the great fairs held twice a year, for the space of twenty days each, at Antwerp, which were thronged by foreigners as well as natives.