The quays of Antwerp were deserted, the industries of Ghent and Bruges destroyed.

The most enterprising and skilful of their merchants and artisans had fled over the frontier into Holland or across the sea into England.

Holland and Zeeland were thronged with refugees, Flemings and Brabanters, French Huguenots and numerous Spanish and Portuguese Jews, driven out by the pitiless persecution of Philip II.
The Hollanders and Zeelanders had long been a seafaring people, who had derived the chief part of their wealth from their fisheries and their carrying trade; and this influx of new and vigorous blood, merchants, traders, and textile workers, bringing with them their knowledge, skill and energy, aroused such a phenomenal outburst of maritime and commercial activity and adventure as the world had never seen before.
The fleets of the Hollanders and Zeelanders had during the whole of the war of independence been the main defence of those provinces against Spanish invasion; but, great as had been the services they had rendered, it was the carrying-trade which had furnished the rebel states with the sinews of war, and of this a large part had been derived from that very trading with the enemy which Leicester had striven in vain to prevent.

The Spaniards and Portuguese were dependent upon the Dutch traders for the supply of many necessaries of life; and thus Spanish gold was made to pay for the support of the war which was waged against the Spanish king.

The dues in connection with this trade, known as licences and convoys, alone furnished large sums to replenish the war-chest; and it is said that from 25,000 to 30,000 seamen found employment by it.
Amsterdam during this decade had been rapidly growing in importance and it was soon to be the first seaport in the world.