After the siege had begun Lieutenant General Sir Alexander Leslie, with 5000 Scots and Swedes, fought his way into the town; and though Wallenstein raised fire upon it, though we were half starved and ravaged by plague, we held out for three months, repulsing every assault, till at last the Imperialists were obliged to draw off; having lost 12,200 men.
"This, however, was the solitary success on our side, and a few months since, Christian signed a peace, binding himself to interfere no more in the affairs of Germany.

When Ferdinand considered himself free to carry out his plans, he issued an edict by which the Protestants throughout Germany were required to restore to the Catholics all the monasteries and land which had formerly belonged to the Catholic Church.

The Catholic service was alone to be performed, and the Catholic princes of the empire were ordered to constrain their subjects, by force if necessary, to conform to the Catholic faith; and it was intimated to the Protestant princes that they would be equally forced to carry the edict into effect.

But this was too much.

Even France disapproved, not from any feeling of pity on the part of Richelieu for the Protestants, but because it did not suit the interests of France that Ferdinand should become the absolute monarch of all Germany.
"In these circumstances Gustavus of Sweden at once resolved to assist the Protestants in arms, and ere long will take the field.