The events of commerce warfare, though they often involve desperate adventures and hard fighting, are not individually impressive, and the effectiveness of this warfare is best measured by collective results. On one occasion, when a fleet of transports fell into the hands of patriot forces off Flushing in 1572, not only were 1000 troops taken, but also 500,000 crowns of gold and a rich cargo, the proceeds of which, it is stated, were sufficient to carry on the whole war for a period of two years. Again it was fear of pirates (Huguenot in this case) that in December of 1568 drove a squadron of Spanish transports into Plymouth, England, with 450,000 ducats ($960,000) aboard for the pay of Spanish troops. Elizabeth seized the money (on the ground that it was still the property of the Genoese bankers who had lent it and that she might as well borrow it as Philip), and minted it into English coin at a profit of L3000. But Alva at Antwerp, with no money at all, was forced to the obnoxious "Hundreds" tax--requiring a payment of one per cent on all possessions, five per cent on all real estate transfers, and 10 per cent every time a piece of merchandise was sold--a typical tax after the Spanish recipe, which, though not finally enforced to its full extent, aroused every Netherlander as a fatal blow at national prosperity. To return to the general effect of commerce destruction, it is estimated that Spain thus lost annually 3,000,000 ducats ($6,400,000), a sum which of course meant vastly more then than now. When the Duke of Alva retired from command in 1578, the pay of Spanish troops was 6,500,000 ducats in arrears. Among the exploits of organized naval forces, the earliest was the capture of Brill, by which, according to Motley, "the foundations of the Dutch republic were laid." Driven out of England by Elizabeth, who upon the representations of the Spanish ambassador ordered her subjects not to supply the Beggars with "meat, bread or beer," a fleet of 25 vessels and 300 or 400 men left Dover towards the end of March, 1572, with the project of seizing a base on their own coast. On the afternoon of April 1, they appeared off the town of Brill, located on an island at the mouth of the Meuse. The magistrates and most of the inhabitants fled; and the Beggars battered down the gates, occupied the town, and put to death 13 monks and priests. When Spanish forces attempted to recapture the city, the defenders opened sluice gates to cut off the northern approach, and at the same time set fire to the boats which had carried the Spanish to the island. The Spanish, terrorized by both fire and water, waded through mud and slime to the northern shore. During the same week Flushing was taken, and before the end of June the Dutch were masters of nearly the entire Zealand coast.