The death of Cardinal Richelieu took place in November, 1642, and the subsequent change in the throne and in the ministry, occasioned by the death of Louis XIII., had for some time withdrawn the attention of France from the German war, and was the cause of the inaction of its troops in the field. But Mazarin, the inheritor, not only of Richelieu's power, but also of his principles and his projects, followed out with renewed zeal the plans of his predecessor, though the French subject was destined to pay dearly enough for the political greatness of his country. The main strength of its armies, which Richelieu had employed against the Spaniards, was by Mazarin directed against the Emperor; and the anxiety with which he carried on the war in Germany, proved the sincerity of his opinion, that the German army was the right arm of his king, and a wall of safety around France. Immediately upon the surrender of Thionville, he sent a considerable reinforcement to Field-Marshal Guebriant in Alsace; and to encourage the troops to bear the fatigues of the German war, the celebrated victor of Rocroi, the Duke of Enghien, afterwards Prince of Conde, was placed at their head. Guebriant now felt himself strong enough to appear again in Germany with repute. He hastened across the Rhine with the view of procuring better winter quarters in Suabia, and actually made himself master of Rothweil, where a Bavarian magazine fell into his hands. But the place was too dearly purchased for its worth, and was again lost even more speedily than it had been taken. Guebriant received a wound in the arm, which the surgeon's unskilfulness rendered mortal, and the extent of his loss was felt on the very day of his death.
The French army, sensibly weakened by an expedition undertaken at so severe a season of the year, had, after the taking of Rothweil, withdrawn into the neighbourhood of Duttlingen, where it lay in complete security, without expectation of a hostile attack. In the mean time, the enemy collected a considerable force, with a view to prevent the French from establishing themselves beyond the Rhine and so near to Bavaria, and to protect that quarter from their ravages. The Imperialists, under Hatzfeldt, had formed a junction with the Bavarians under Mercy; and the Duke of Lorraine, who, during the whole course of the war, was generally found everywhere except in his own duchy, joined their united forces. It was resolved to force the quarters of the French in Duttlingen, and the neighbouring villages, by surprise; a favourite mode of proceeding in this war, and which, being commonly accompanied by confusion, occasioned more bloodshed than a regular battle. On the present occasion, there was the more to justify it, as the French soldiers, unaccustomed to such enterprises, conceived themselves protected by the severity of the winter against any surprise. John de Werth, a master in this species of warfare, which he had often put in practice against Gustavus Horn, conducted the enterprise, and succeeded, contrary to all expectation.
The attack was made on a side where it was least looked for, on account of the woods and narrow passes, and a heavy snow storm which fell upon the same day, (the 24th November, 1643,) concealed the approach of the vanguard till it halted before Duttlingen. The whole of the artillery without the place, as well as the neighbouring Castle of Honberg, were taken without resistance, Duttlingen itself was gradually surrounded by the enemy, and all connexion with the other quarters in the adjacent villages silently and suddenly cut off. The French were vanquished without firing a cannon. The cavalry owed their escape to the swiftness of their horses, and the few minutes in advance, which they had gained upon their pursuers. The infantry were cut to pieces, or voluntarily laid down their arms. About 2,000 men were killed, and 7,000, with 25 staff-officers and 90 captains, taken prisoners. This was, perhaps, the only battle, in the whole course of the war, which produced nearly the same effect upon the party which gained, and that which lost; -- both these parties were Germans; the French disgraced themselves. The memory of this unfortunate day, which was renewed 100 years after at Rosbach, was indeed erased by the subsequent heroism of a Turenne and Conde; but the Germans may be pardoned, if they indemnified themselves for the miseries which the policy of France had heaped upon them, by these severe reflections upon her intrepidity.
Meantime, this defeat of the French was calculated to prove highly disastrous to Sweden, as the whole power of the Emperor might now act against them, while the number of their enemies was increased by a formidable accession. Torstensohn had, in September, 1643, suddenly left Moravia, and moved into Silesia. The cause of this step was a secret, and the frequent changes which took place in the direction of his march, contributed to increase this perplexity. From Silesia, after numberless circuits, he advanced towards the Elbe, while the Imperialists followed him into Lusatia. Throwing a bridge across the Elbe at Torgau, he gave out that he intended to penetrate through Meissen into the Upper Palatinate in Bavaria; at Barby he also made a movement, as if to pass that river, but continued to move down the Elbe as far as Havelburg, where he astonished his troops by informing them that he was leading them against the Danes in Holstein.
The partiality which Christian IV. had displayed against the Swedes in his office of mediator, the jealousy which led him to do all in his power to hinder the progress of their arms, the restraints which he laid upon their navigation of the Sound, and the burdens which he imposed upon their commerce, had long roused the indignation of Sweden; and, at last, when these grievances increased daily, had determined the Regency to measures of retaliation. Dangerous as it seemed, to involve the nation in a new war, when, even amidst its conquests, it was almost exhausted by the old, the desire of revenge, and the deep-rooted hatred which subsisted between Danes and Swedes, prevailed over all other considerations; and even the embarrassment in which hostilities with Germany had plunged it, only served as an additional motive to try its fortune against Denmark.
Matters were, in fact, arrived at last to that extremity, that the war was prosecuted merely for the purpose of furnishing food and employment to the troops; that good winter quarters formed the chief subject of contention; and that success, in this point, was more valued than a decisive victory. But now the provinces of Germany were almost all exhausted and laid waste. They were wholly destitute of provisions, horses, and men, which in Holstein were to be found in profusion. If by this movement, Torstensohn should succeed merely in recruiting his army, providing subsistence for his horses and soldiers, and remounting his cavalry, all the danger and difficulty would be well repaid. Besides, it was highly important, on the eve of negotiations for peace, to diminish the injurious influence which Denmark might exercise upon these deliberations, to delay the treaty itself, which threatened to be prejudicial to the Swedish interests, by sowing confusion among the parties interested, and with a view to the amount of indemnification, to increase the number of her conquests, in order to be the more sure of securing those which alone she was anxious to retain. Moreover, the present state of Denmark justified even greater hopes, if only the attempt were executed with rapidity and silence. The secret was in fact so well kept in Stockholm, that the Danish minister had not the slightest suspicion of it; and neither France nor Holland were let into the scheme. Actual hostilities commenced with the declaration of war; and Torstensohn was in Holstein, before even an attack was expected. The Swedish troops, meeting with no resistance, quickly overran this duchy, and made themselves masters of all its strong places, except Rensburg and Gluckstadt. Another army penetrated into Schonen, which made as little opposition; and nothing but the severity of the season prevented the enemy from passing the Lesser Baltic, and carrying the war into Funen and Zealand. The Danish fleet was unsuccessful at Femern; and Christian himself, who was on board, lost his right eye by a splinter. Cut off from all communication with the distant force of the Emperor, his ally, this king was on the point of seeing his whole kingdom overrun by the Swedes; and all things threatened the speedy fulfilment of the old prophecy of the famous Tycho Brahe, that in the year 1644, Christian IV. should wander in the greatest misery from his dominions.