Norby was at this time the most valuable officer that Christiern had. He infested the shores of the Baltic with his fleet, making frequent incursions on the land to plunder; and at length became so obnoxious that Gustavus sent to Lubeck for a fleet. On the 7th of June it came, ten ships of war, laden with all sorts of merchandise, and fully equipped with powder, shot, and men. For this aid Gustavus is said to have paid an enormous figure, giving his promissory note for the amount. Picking out a battalion of five hundred men, he sent them down to Kalmar, to which castle Vestgöte had just laid siege. The rest of the reinforcements he despatched to Stockholm, quartering them in his different camps, and then discharged all of the Swedish peasants except the young unmarried men. Shortly after this change the commandant of Åbo Castle crossed the Baltic with a powerful fleet, and sought to break the siege of Stockholm. But the Swedish fleet met him outside the harbor, captured or burnt his vessels, and took him prisoner. In October, seeing that the garrison was losing strength, Gustavus advanced his camps nearer to the town. His southern camp he moved to Södermalm, from which he built a pontoon bridge to connect it with the west camp now on an island some three or four hundred yards from Stockholm. Another bridge he threw across the channel east of the city, and built upon it a turret which he armed with heavy guns. The city was thus hemmed in on every side, and a contemporary writes, "We cannot find in any of the old chronicles that Stockholm ever was so hard besieged before." Unless relief came it was merely a question of time when the garrison would have to yield. Once, in November, Norby came sailing into the harbor with five ships-of-war; but the Swedish fleet, consisting of fifteen vessels, drove him off, and, were it not for the half-heartedness of the German mercenaries, would very likely have destroyed his fleet.[69]