In 1521 the French were driven from the Duchy of Milan and in 1522 they were compelled to retire from Italy. In the following year the Constable of Bourbon deserted Francis to espouse the Emperor's cause, because he had received many insults from court favourites. He had been removed from the government of Milan, and was fond of quoting the words of an old Gascon knight first spoken in the reign of Charles VII: "Not three kingdoms like yours could make me forsake you, but one insult might."
Bourbon was rebuked for his faithlessness to his King at the battle of La Biagrasse where Bayard, that perfect knight, sans peur et sans reproche, fell with so many other French nobles. The Constable had compassion on the wounded man as he lay at the foot of a tree with his face still turned to the enemy. "Sir, you need have no pity for me," the knight answered bravely, "for I die an honest man; but I have pity on you, seeing you serve against your prince, your country, and your oath."
Bourbon may have blushed at the rebuke, but he took the field gallantly at Pavia on behalf of the Emperor. Francis I had invaded Italy and occupied Milan, but he was not quick to follow up his success and met defeat at the hands of his vassal on February 24th, 1525, which was Charles V's twenty-fifth birthday. The flower of France fell on the battle-field, while the King himself was taken prisoner. He would not give up his sword to the traitor Bourbon, but continued to fight on foot after his horse had been shot under him. He proved that he was as punctilious a knight as Bayard, and wrote to his mother on the evening of this battle, "All is lost but honour."
The Emperor's army now had both France and Italy at their mercy. Bourbon decided to march on Rome, to the joy of his needy, avaricious soldiers. He took the ancient capital where the riches of centuries had accumulated; both Spaniards and Germans rioted on its treasures without restraint. They spared neither church nor palace, but defiled the most sacred places. The very ring was removed from the hand of Pope Julius as he lay within his tomb. Clement VII, the reigning Pope, was too feeble and vacillating to save himself, though it would have been quite possible. He was made a prisoner of war, for political motives inspired the Emperor to demand a heavy ransom.
The Ladies' Peace concluded the long war between Charles V and Francis I. It was so called because it was arranged through Louise, the French King's mother, and Margaret, the aunt who had taken charge of the Emperor in his childhood. These two ladies occupied adjoining houses in the town of Cambrai, and held consultations at any hour in the narrow passage between the two dwellings. The peace, finally drawn up in August 1529, was very shameful to Francis I, since he agreed to desert all his partisans in Italy and the Netherlands. He had purchased his own freedom by the treaty of Madrid in 1526.
In 1530, the Emperor, who had made a separate treaty with the Italian states, received the crown of Lombardy and crown of the Holy Roman Empire from the hands of the Pope at Bologna. On this occasion he was invested with a mantle studded with jewels and some ancient sandals. Ill-health and increasing melancholy clouded his delight in these honours. His aquiline features and dark colouring had formerly given him some claim to beauty, but now the heavy "Hapsburg" jaw began to show the settled obstinacy of a narrow nature. The iron crown of Italy weighed on him heavily, for he was stricken by remorse that he had disregarded the entreaties of the Pope for the rescue of the Knights of St John, whose settlement of Rhodes had been attacked by the Turkish infidels. He gave them Malta in order that he might appease his conscience. Religion claimed much of his attention after the long conflict with France was ended.
Heresy was spreading in Germany, where Luther gained a vast number of adherents. Charles issued an edict against the monk, but there was national resistance for him to face as a consequence. In 1530 he renewed the Edict of Worms and was opposed by a League of Protestant princes, who applied for help from England, France, and Denmark against the oppressive Emperor. He would have set himself to crush them if his dominions had not been menaced by Soliman the Magnificent, a Turkish Sultan with an immense army. He was obliged to secure the co-operation of the Protestants against the Turks that he might drive the latter from his eastern frontier.
Italians, Flemings, Hungarians, Bohemians, and Burgundians fought side by side with the German troops and drove the invader back to his own territory. When this danger was averted, France suddenly attacked Savoy, and the Emperor found that he must postpone his struggle with the Lutherans. A joint invasion of France by Charles V and Henry VIII of England forced Francis to conclude humiliating peace at Crespy 1544. Three years later the death of the French King left his adversary free to crush the religious liberty of his German subjects.
The Emperor, who had declared himself on the side of the Papacy in 1521, now united with the Pope and Charles' brother Ferdinand, who had been given the government of all the Austrian lands. All three were determined to compel Germany to return to the old faith and the old subjection to the Empire. Their resolve seemed to be fulfilled when Maurice, Duke of Saxony, betrayed the Protestant cause, the allies of the German princes proved faithless, and the Elector of Saxony and the Landgrave of Hesse were taken prisoners at Muhlberg in April 1547.
The star of Austria was still in the ascendant, and Charles V could still quote his favourite phrase, "Myself and the lucky moment." He put Maurice in the place of the venerable Elector of Saxony, who had refused long ago to take a bribe, and let the Landgrave of Hesse lie in prison. He imagined that he had Germany at his feet, and exulted over the defenders of her freedom. There had been a faint hope in their hearts once that the Emperor would champion Luther's cause from political interest, but he did not need a weapon against the Pope since the Holy See was entirely subservient to his wishes. Bigotry, inherited from Spanish ancestors, showed itself in the Emperor now. In Spain and the Netherlands he used the terrible Inquisition to stamp out heresy. The Grand Inquisitors, who charged themselves with the religious welfare of these countries, claimed control over lay and clerical subjects in the name of their ruler.