On the other hand, the commerce and manufactures of the United Republic had enormously augmented.  Its bitterest enemies bore witness to the sagacity and success by which its political affairs were administered, and to its vast superiority in this respect over the obedient provinces.  “The rebels are not ignorant of our condition,” said Champagny, “they are themselves governed with consummate wisdom, and they mock at those who submit themselves to the Duke of Parma.  They are the more confirmed in their rebellion, when they see how many are thronging from us to them, complaining of such bad government, and that all take refuge in flight who can from the misery and famine which it has caused throughout these provinces!” The industrial population had flowed from the southern provinces into the north, in obedience to an irresistible law.  The workers in iron, paper, silk, linen, lace, the makers of brocade, tapestry, and satin, as well as of all the coarser fabrics, had fled from the land of oppression to the land of liberty.  Never in the history of civilisation had there been a more rapid development of human industry than in Holland during these years of bloodiest warfare.  The towns were filled to overflowing.  Amsterdam multiplied in wealth and population as fast as Antwerp shrank.  Almost as much might be said of Middelburg, Enkhuyzen, Horn, and many other cities.  It is the epoch to which the greatest expansion of municipal architecture is traced.  Warehouses, palaces, docks, arsenals, fortifications, dykes, splendid streets and suburbs, were constructed on every side, and still there was not room for the constantly increasing population, large numbers of which habitually dwelt in the shipping.  For even of that narrow span of earth called the province of Holland, one-third was then interior water, divided into five considerable lakes, those of Harlem, Schermer, Beemster, Waert, and Purmer.  The sea was kept out by a magnificent system of dykes under the daily superintendence of a board of officers, called dyke-graves, while the rain-water, which might otherwise have drowned the soil thus painfully reclaimed, was pumped up by windmills and drained off through sluices opening and closing with the movement of the tides.

The province of Zeeland was one vast “polder.”  It was encircled by an outer dyke of forty Dutch equal to one hundred and fifty English, miles in extent, and traversed by many interior barriers.  The average cost of dyke-building was sixty florins the rod of twelve feet, or 84,000 florins the Dutch mile.  The total cost of the Zeeland dykes was estimated at 3,360,000 florins, besides the annual repairs.