Richelieu took his measures promptly. In 1624 he helped to bring about a marriage alliance between Charles prince of Wales and Henrietta Maria, the sister of Louis XIII., by which he hoped to gain the assistance of England against Spain on the sea and in the Netherlands, while he struck at the Valtelline. An army of the mountaineers of the Grisons under French leadership drove the imperial troops from Chur, and the papal troops from the Valtelline, where they had replaced the Spaniards. Lesdiguières, at the head of a French force, marched to the assistance of Savoy against Genoa. But just at that time the Huguenots of La Rochelle flew to arms, and Richelieu, afraid of finding himself involved at once in war at home and abroad, came to terms with Spain at the treaty of Monzon, concluded in March 1626, by which the Valtelline was to remain under the control of the Grisons.
The Mantuan succession, 1627.
For the next three years the whole energies of Richelieu and of France were engaged in the reduction of La Rochelle, and in the war with England, which followed hard upon, and indeed sprung out of, the marriage treaty of 1624. In 1629 he was once more at liberty to turn his attention to Italian affairs. In 1627 the duke of Mantua and Montferrat had died. His nearest heir was a Frenchman, the duke of Nevers. But the Emperor, at the instigation of Spain, not wishing to have a French prince so near the Milanese, determined to sequester the territory on the pretext of a disputed succession. Spanish troops at once overran both Mantua and Montferrat, and driving the duke of Nevers into Casale besieged him there. The Italian princes, however, were not inclined to submit without protest to this exercise by the Emperor of obsolete and doubtful rights. The Pope (Urban VIII.), who was strongly French in sympathy, combined with Venice to ask the assistance of France, and in January 1629 Louis and Richelieu crossed the Mont Genèvre at the head of a large army, captured Susa, relieved Casale, and forced the duke of Savoy to make peace. Again, however, a rebellion of the Huguenots obliged Louis to draw back in the hour of victory (March 1629), and in the summer of that year fresh troops, set free by the imperialist successes in Germany, invaded Italy under Spinola and formed the sieges of Mantua and Casale. In spite of the most strenuous efforts of Louis himself, who crossed the Alps at the head of the French armies in the winter of 1629–30, the combined forces of Spain and the Empire were too strong to be dislodged from Mantua or Montferrat. Peace of Cherasco, 1631. But the invasion of Germany by Gustavus Adolphus, promoted by France and even by the Pope, made the Emperor anxious for peace, and through the diplomatic skill of the papal agent, Giulio Mazzarini—afterwards to become so celebrated in French history—a truce was arranged, which afterwards ripened into the definitive peace of Cherasco (April 26th, 1631). By this treaty the duke of Nevers was invested with the duchy, and the fortresses were restored on both sides, except Pinerolo, which was still held by the French.
So ended the first great effort made by Richelieu against the House of Habsburg. Like most of his plans it was better conceived than executed, but it must be remembered that in carrying it out, he was sorely hampered by opposition to his authority at home both from the Huguenots and from the nobles. His Italian policy must not be considered by itself. It is part of a great whole. While he was openly attacking the imperial forces in Italy, his diplomacy was undermining the imperialist power in Germany, and if in 1631 he thought it best to rest content with the reduction of Savoy, and the acquisition of a passage through the Alps, it was because at that particular moment he could best effect his purpose by shifting his method from direct to indirect hostility, and the scene from Italy to Germany.
Intrigues of Richelieu in Germany, 1630.
Already he had endeavoured to keep the flame of opposition to Spain alive by granting subsidies to the Dutch, and directing Mansfeld’s army in 1624 to the Netherlands. In July 1630, he sent his most trusted agent the famous Capuchin, Father Joseph, to the meeting of the diet of Regensburg, where he laboured with notable skill and success to bring about the dismissal of Wallenstein, and to pave the way for detaching Maximilian of Bavaria and the League from their close alliance with the Emperor and Spain. In the autumn of the year before, another well-trained diplomatist, Charnacé, had travelled as far as Dantzig to offer the mediation of France in the quarrel between Sweden and Poland, and so removed one of the obstacles which made Gustavus Adolphus hesitate to take part in the German War. At that time Richelieu seems to have thought that he could use Gustavus merely as a fighting tool, and by offering him French money and a French alliance could make him fight the battles of France against the Emperor. But he was quickly undeceived. Gustavus definitely refused to allow his political or military independence to be impaired. He was quite willing that France should interfere openly in the war, if she chose to do so, provided she would limit her operations to the left bank of the Rhine; but he would not tolerate for a moment any interference with his own command. The utmost that Richelieu could obtain from him by the treaty of Bärwalde in 1631, in return for French gold, was the promise to observe friendship or neutrality towards Bavaria and the League, so far as they would observe them towards him. Nor was this promise of much avail, for when, after the battle of Breitenfeld, Gustavus determined to march upon central and southern Germany instead of on Vienna, all hope of detaching Bavaria from the Emperor had to be laid aside.
Open interference in Germany, 1632–1634.
As long as Gustavus Adolphus lived there was but little room for Richelieu in German politics. Had he survived a few years longer, it is not improbable that the world would have seen an alliance of the Moderates in Germany, under the leadership of Richelieu, supported possibly by both Maximilian and Wallenstein, against the Emperor and the king of Sweden. But the death of Gustavus quickly put the decisive voice in German affairs into the possession of France. Already in 1632 French troops had appeared upon the Rhine, and garrisoned the new fortress of Ehrenbreitstein at the invitation of the elector of Trier. In the same year Richelieu became a party to the League of Heilbronn, and so secured the right to interfere in German affairs. In 1633 a French army entered the old German territory of Lorraine and captured its capital Nancy, owing to the incessant intrigues against the all-powerful cardinal of which the duke had been guilty. The battle of Nördlingen in 1634 put Protestant Germany at the feet of Richelieu. The soil of Germany, harried and plundered, could with difficulty sustain the armies which devastated it. Sweden, poor and exhausted, could make no sacrifices. England was too much occupied with pecuniary difficulties at home to be able to send assistance to Germany. Declaration of war against Spain, 1635. France was the only power both able and willing to provide the sinews of war. She became the protector and director of the League of Heilbronn, took Bernhard of Saxe-Weimar and his army into her pay, claimed from the Swedes the custody of the fortresses held by them in Alsace, and on 19th May 1635 formally declared war against Spain.
The character of the war altered by French interference.
From that moment the character of the Thirty Years’ War profoundly alters. It is no longer a war of religion, to set limits to the progress of the Counter-Reformation or to save Catholicism or Protestantism from extinction. It is no longer a war of institutions, to maintain the authority of the Emperor or to preserve the sovereign rights of the princes. It is no longer a war of property, to resist the undoing of the territorial settlement of 1555. It is no longer a war for the re-settlement of Germany upon a new basis by military force. German interests no longer have a place in this terrible war waged for the destruction of Germany on German soil. Primarily, it is a war between the House of Bourbon and the House of Habsburg, to break the power of Spain and increase that of France, through the acquisition by the latter of Alsace and Lorraine. Secondarily, it is a war between the Swedes and the Empire, to gain for the former out of German soil an adequate compensation for the money which they had spent and the blood which they had shed. Two points of interest alone remain in tracing the melancholy story of the weary years, the gradual development of the power of France, and the brilliant achievements of skilful generalship.