In preparation for enforcing the decrees which he intended to have enacted by the council of Trent, Charles obtained from the pope thirteen thousand troops, and five hundred thousand ducats (one million one hundred thousand dollars).  He raised one army in the Low Countries to march upon Germany.  He gathered another army in his hereditary States of Austria.  His brother Ferdinand, as King of Hungary and Bohemia, raised a large army in each of those dominions.  The King of France mustered his legions, and boasted of the condign punishment to which he would consign the heretics.  The pope issued a decree offering the entire pardon of all sins to those who should engage in this holy war for the extirpation of the doctrines of the reformers.

The Protestants were for a moment in consternation in view of the gatherings of so portentous a storm.  The emperor, by false professions and affected clemency, had so deceived them that they were quite unprepared for so formidable an attack.  They soon, however, saw that their only salvation depended upon a vigorous defense, and they marshaled their forces for war.  With promptness and energy which even astonished themselves, they speedily raised an army which, on the junction of its several corps, amounted to eighty thousand men.  In its intelligence, valor, discipline and equipments, it was probably the best army which had ever been assembled in the States of Germany.  Resolutely they marched under Schartlin, one of the most experienced generals of the age, toward Ratisbon, where the emperor was holding a diet.

Charles V. was as much alarmed by this unexpected apparition, as the Protestants had been alarmed by the preparations of the emperor.  He had supposed that his force was so resistless that the Protestants would see at once the hopelessness of resistance, and would yield without a struggle.  The emperor had a guard of but eight thousand troops at Ratisbon.  The Duke of Bavaria, in whose dominions he was, was wavering, and the papal troops had not commenced their march.  But there was not a moment to be lost.  The emperor himself might be surrounded and taken captive.  He retired precipitately about thirty miles south to the strong fortress of Landshut, where he could hold out until he received succor from his Austrian territories, which were very near, and also from the pope.

Charles soon received powerful reinforcements from Austria, from the pope, and from his Spanish kingdom.  With these he marched some forty miles west to Ingolstadt and intrenched himself beneath its massive walls.  Here he waited for further reinforcements, and then commencing the offensive, marched up the Danube, taking possession of the cities on either bank.  And now the marshaled forces of the emperor began to crowd the Protestants on all sides.  The army became bewildered, and instead of keeping together, separated to repel the attack at different points.  This caused the ruin of the Protestant army.  The dissevered fragments were speedily dispersed.  The emperor triumphantly entered the Protestant cities of Ulm and Augsburg, Strasbourg and Frankfort, compelled them to accept humiliating conditions, to surrender their artillery and military stores, and to pay enormous fines.  The Archbishop of Cologne was deposed from his dignities.  The emperor had thrown his foes upon the ground and bound them.