The Danish king sued for peace, and his possessions were returned to him on condition that he would take no further part in the war. This concession was not from mercy, but because France and Sweden were now preparing to take arms against the House of Austria.
In the conference at Lubeck, on May 22d, 1629, Wallenstein, with marked contempt, excluded the Swedish ambassadors while arranging terms with Denmark.
Wallenstein had been so successful that he had visions of making himself Emperor, of converting the Baltic Sea into an Austrian lake, and there having a great fleet to increase his wealth and power. For these reasons he now set out to take the cities on the Baltic coast. He besieged Stralsund, a Hanse town. The Hanse towns were the commercial towns of Germany, associated together for the protection of commercial interests. Wallenstein now had the title of "Admiral of the Baltic" conferred on him by the Emperor. The new admiral said, "There are twenty-eight ports in Pomerania; we must fortify them to keep Sweden from attacking them."
Stralsund represented not alone the Hanseatic League, but the Protestant faith and liberty of conscience. Wallenstein swore, "I will capture Stralsund though it were chained to the gates of heaven." He did not take into the count God and the king of Sweden.
The inhabitants of Stralsund were a deeply religious people. With Wallenstein besieging their city, and well knowing the destruction of the country over which they had passed, they took the oath to abide by the true religion of the Augsburg Confession, to fight for it as well as for the rights and liberties of the city, and to stand by the Empire as long as the line of conduct would be justifiable before God, posterity, and in accordance with their oath to defend the city. This shows their faith in God; to Him they appealed, and after ten weeks siege, Wallenstein, at the order of the Emperor, after losing twelve thousand of his best troops, was forced to abandon the siege.
Wallenstein had threatened to destroy every creature within its walls, so the women and children had been sent to Sweden, and that country provided the food from the side of Stralsund opening on the sea.
But the Emperor now considered that his troops were so successful that he might put into the form of an edict that which they had been practicing ever since his coronation. He issued what is called the Edict of Restitution (1629 A. D.), confiscating all Protestant property obtained from Catholics since the Treaty of Passau. This violated the Treaty of Augsburg, which had guaranteed that property. This would have made war in time of peace, now it prolonged a war begun eleven years before. He further decided "that by the religious peace Catholic princes were under no further obligations to their Protestant subjects than to allow them to quit their territories."
Under this edict the Protestant States were ordered to surrender all church property and all secularized religious foundations to the Imperial commissioner. The Protestants again quite understood that the extermination of their religion had been determined. The commissioners were appointed, and Wallenstein was charged to enforce the edict.
The enforcement began at Augsburg. The bishop was reinstated. He prohibited all worship of the Protestant form, and erected a gallows in front of the town hall to show what would happen to those who disobeyed.
Lorenz Forer, one of Wallenstein's captains, said, "Be active, my friends, if some withstand you, kill and burn them in a fire that shall make the stars melt, and force the angels of heaven to withdraw their feet."