Gustavus now learned definitely that Norby, ever since his fleet left Gotland, had been in secret conspiracy with Mehlen. He determined, therefore, that, since the pirate had gained a foothold on the mainland, Kalmar must be secured at any risk. So he collected men from every quarter and sent them down to Kalmar to reinforce the town. Some few weeks later, as the castle had not yielded, he proceeded to the town himself. The burghers, hoping the conflict would now be ended, welcomed him with joy. But the garrison still believed in Mehlen, and confidently awaited his return with aid. Gustavus sent an envoy to the castle, to persuade the garrison to yield. The answer was, the garrison would not be yielded till every one of them was dead. But one course, therefore, was open to the monarch,--the castle must be stormed. This, with the guns which he possessed, demanded almost more than human strength. The castle was surrounded on all sides by a moat, beyond which rose a perpendicular wall of masonry twenty feet in height. This rampart was washed on three sides by the sea, and on the other was protected by a broad deep dike and then an outer wall. From within, the rampart was guarded by eight huge towers that stood out from the castle-walls, and the four corners of the ramparts were further strengthened by four more towers with apertures for crossbows, cannon, and muskets. Such was the fortress that Gustavus, late in July, resolved to storm. He began by throwing up a line of earthworks, behind which he placed his heavy guns, hoping to batter down the towers and ramparts, while his pikemen and halberdiers were scaling the unprotected parts. But his men at first were lukewarm. The task seemed herculean, and every effort to ascend the ramparts met with certain death. Those in the castle fought like maniacs, the men with guns and crossbows, and the women firing stones. Gustavus, it is reported, stormed and swore, and finally put on his armor, declaring that he would either have the castle or die within its walls. His enthusiasm spread among his men, and they shouted they would do their best, though every man of them should fall. The effect was visible at once. Each charge left the ramparts weaker than before; and when night closed in, there was not a tower or rampart whole. The next morning, when Gustavus turned his culverins again upon the wall, the flag of truce was raised. The garrison hoped that if they sued before the ramparts actually fell, they might be granted favorable terms. But the monarch, who had now lost nearly half his men, demanded an unconditional surrender. As Norby had been conquered, and no signs of Mehlen's succor had appeared, the garrison, after much palaver, threw themselves upon the mercy of the king. The castle, on the 20th of July, passed into the monarch's hands once more, and a large portion of the rebel garrison was put to death. With this scene the conspiracy of Norby, Mehlen, and their adherents was at an end.[121]