When Ferdinand’s fortunes were at a low ebb, and he knew not in which way to find either money or an army, Wallenstein offered to raise fifty thousand men at his own expense, to pay their wages, supply them with arms and all the munitions of war, and to call upon the emperor for no pecuniary assistance whatever, if the emperor would allow him to retain the plunder he could extort from the conquered. Upon this majestic scale Wallenstein planned to act the part of a highwayman. Ferdinand’s necessities were so great that he gladly availed himself of this infamous offer. Wallenstein made money by the bargain. Wherever he marched he compelled the people to support his army, and to support it luxuriously. The emperor had now constituted him admiral of the Baltic fleet, and had conferred upon him the title of duke, with the splendid duchy of Mecklenburg, and the principality of Sagan in Silesia. His overbearing conduct and his enormous extortions—he having, in seven years, wrested from the German princes more than four hundred million of dollars—excited a general feeling of discontent, in which the powerful Duke of Bavaria took the lead.
Envy is a stronger passion than political religion. Zealous as the Duke of Bavaria had been in the cause of the papal church, he now forgot that church in his zeal to abase an arrogant and insulting rival. Richelieu, the prime minister of France, was eagerly watching for opportunities to humiliate the house of Austria, and he, with alacrity, met the advances of the Duke of Bavaria, and conspired with him to form a Catholic league, to check the ambition of Wallenstein, and to arrest the enormous strides of the emperor. With this object in view, a large number of the most powerful Catholic princes met at Heidelberg, in March, 1629, and passed resolutions soliciting Ferdinand to summon a diet of the German empire to take into consideration the evils occasioned by the army of Wallenstein, and to propose a remedy. The emperor had, in his arrogance, commanded the princes of the various States in the departments of Suabia and Franconia, to disband their troops. To this demand they returned the bold and spirited reply,
“Till we have received an indemnification, or a pledge for the payment of our expenses, we will neither disband a single soldier, nor relinquish a foot of territory, ecclesiastical or secular, demand it who will.”