The reign of Philip the Good was marked by a great advance in the material prosperity of the land. Bruges, Ghent, Ypres and Antwerp were among the most flourishing commercial and industrial cities in the world, and when, through the silting up of the waterway, Bruges ceased to be a seaport, Antwerp rapidly rose to pre-eminence in her place, so that a few decades later her wharves were crowded with shipping, and her warehouses with goods from every part of Europe. In fact during the whole of the Burgundian period the southern Netherlands were the richest domain in Christendom, and continued to be so until the disastrous times of Philip II of Spain. Meanwhile Holland and Zeeland, though unable to compete with Brabant and Flanders in the populousness of their towns and the extent of their trade, were provinces of growing importance. Their strength lay in their sturdy and enterprising sea-faring population. The Hollanders had for many years been the rivals of the Hanse Towns for the Baltic trade. War broke out in 1438 and hostilities continued for three years with the result that the Hanse League was beaten, and henceforth the Hollanders were able without further let or hindrance more and more to become the chief carriers of the "Eastland" traffic. Amsterdam was already a flourishing port, though as yet it could make no pretension of competing with Antwerp. The herring fisheries were, however, the staple industry of Holland and Zeeland. The discovery of the art of curing herrings by William Beukelsz of Biervliet (died 1447) had converted a perishable article of food into a marketable commodity; and not only did the fisheries give lucrative employment to many thousands of the inhabitants of these maritime provinces, but they also became the foundation on which was to be built their future commercial supremacy. The Burgundian dukes were among the most powerful rulers of their time--the equals of kings in all but name--and they far surpassed all contemporary sovereigns in their lavish display and the splendour of their court. The festival at Bruges in 1430 in celebration of the marriage of Philip the Good and Isabel of Portugal, at which the Order of the Golden Fleece was instituted, excited universal wonder; while his successor, Charles the Bold, contrived to surpass even his father in the splendour of his espousals with Margaret of York in 1468, and at his conference with the Emperor Frederick III at Trier in 1473. On this last occasion he wore a mantle encrusted all over with diamonds.