I may now be permitted to take a cursory retrospect of Gustavus Adolphus in his victorious career; glance at the scene in which he alone was the great actor; and then, when Austria becomes reduced to extremity by the successes of the Swedes, and by a series of disasters is driven to the most humiliating and desperate expedients, to return to the history of the Emperor.
As soon as the plan of operations had been concerted at Halle, between the King of Sweden and the Elector of Saxony; as soon as the alliance had been concluded with the neighbouring princes of Weimar and Anhalt, and preparations made for the recovery of the bishopric of Magdeburg, the king began his march into the empire. He had here no despicable foe to contend with. Within the empire, the Emperor was still powerful; throughout Franconia, Swabia, and the Palatinate, imperial garrisons were posted, with whom the possession of every place of importance must be disputed sword in hand. On the Rhine he was opposed by the Spaniards, who had overrun the territory of the banished Elector Palatine, seized all its strong places, and would everywhere dispute with him the passage over that river. On his rear was Tilly, who was fast recruiting his force, and would soon be joined by the auxiliaries from Lorraine. Every Papist presented an inveterate foe, while his connexion with France did not leave him at liberty to act with freedom against the Roman Catholics. Gustavus had foreseen all these obstacles, but at the same time the means by which they were to be overcome. The strength of the Imperialists was broken and divided among different garrisons, while he would bring against them one by one his whole united force. If he was to be opposed by the fanaticism of the Roman Catholics, and the awe in which the lesser states regarded the Emperor's power, he might depend on the active support of the Protestants, and their hatred to Austrian oppression. The ravages of the Imperialist and Spanish troops also powerfully aided him in these quarters; where the ill-treated husbandman and citizen sighed alike for a deliverer, and where the mere change of yoke seemed to promise a relief. Emissaries were despatched to gain over to the Swedish side the principal free cities, particularly Nuremberg and Frankfort. The first that lay in the king's march, and which he could not leave unoccupied in his rear, was Erfurt. Here the Protestant party among the citizens opened to him, without a blow, the gates of the town and the citadel. From the inhabitants of this, as of every important place which afterwards submitted, he exacted an oath of allegiance, while he secured its possession by a sufficient garrison. To his ally, Duke William of Weimar, he intrusted the command of an army to be raised in Thuringia. He also left his queen in Erfurt, and promised to increase its privileges. The Swedish army now crossed the Thuringian forest in two columns, by Gotha and Arnstadt, and having delivered, in its march, the county of Henneberg from the Imperialists, formed a junction on the third day near Koenigshofen, on the frontiers of Franconia.
Francis, Bishop of Wurtzburg, the bitter enemy of the Protestants, and the most zealous member of the League, was the first to feel the indignation of Gustavus Adolphus. A few threats gained for the Swedes possession of his fortress of Koenigshofen, and with it the key of the whole province. At the news of this rapid conquest, dismay seized all the Roman Catholic towns of the circle. The Bishops of Wurtzburg and Bamberg trembled in their castles; they already saw their sees tottering, their churches profaned, and their religion degraded. The malice of his enemies had circulated the most frightful representations of the persecuting spirit and the mode of warfare pursued by the Swedish king and his soldiers, which neither the repeated assurances of the king, nor the most splendid examples of humanity and toleration, ever entirely effaced. Many feared to suffer at the hands of another what in similar circumstances they were conscious of inflicting themselves. Many of the richest Roman Catholics hastened to secure by flight their property, their religion, and their persons, from the sanguinary fanaticism of the Swedes. The bishop himself set the example. In the midst of the alarm, which his bigoted zeal had caused, he abandoned his dominions, and fled to Paris, to excite, if possible, the French ministry against the common enemy of religion.
The further progress of Gustavus Adolphus in the ecclesiastical territories agreed with this brilliant commencement. Schweinfurt, and soon afterwards Wurtzburg, abandoned by their Imperial garrisons, surrendered; but Marienberg he was obliged to carry by storm. In this place, which was believed to be impregnable, the enemy had collected a large store of provisions and ammunition, all of which fell into the hands of the Swedes. The king found a valuable prize in the library of the Jesuits, which he sent to Upsal, while his soldiers found a still more agreeable one in the prelate's well-filled cellars; his treasures the bishop had in good time removed. The whole bishopric followed the example of the capital, and submitted to the Swedes. The king compelled all the bishop's subjects to swear allegiance to himself; and, in the absence of the lawful sovereign, appointed a regency, one half of whose members were Protestants. In every Roman Catholic town which Gustavus took, he opened the churches to the Protestant people, but without retaliating on the Papists the cruelties which they had practised on the former. On such only as sword in hand refused to submit, were the fearful rights of war enforced; and for the occasional acts of violence committed by a few of the more lawless soldiers, in the blind rage of the first attack, their humane leader is not justly responsible. Those who were peaceably disposed, or defenceless, were treated with mildness. It was a sacred principle of Gustavus to spare the blood of his enemies, as well as that of his own troops.
On the first news of the Swedish irruption, the Bishop of Wurtzburg, without regarding the treaty which he had entered into with the King of Sweden, had earnestly pressed the general of the League to hasten to the assistance of the bishopric. That defeated commander had, in the mean time, collected on the Weser the shattered remnant of his army, reinforced himself from the garrisons of Lower Saxony, and effected a junction in Hesse with Altringer and Fugger, who commanded under him. Again at the head of a considerable force, Tilly burned with impatience to wipe out the stain of his first defeat by a splendid victory. From his camp at Fulda, whither he had marched with his army, he earnestly requested permission from the Duke of Bavaria to give battle to Gustavus Adolphus. But, in the event of Tilly's defeat, the League had no second army to fall back upon, and Maximilian was too cautious to risk again the fate of his party on a single battle. With tears in his eyes, Tilly read the commands of his superior, which compelled him to inactivity. Thus his march to Franconia was delayed, and Gustavus Adolphus gained time to overrun the whole bishopric. It was in vain that Tilly, reinforced at Aschaffenburg by a body of 12,000 men from Lorraine, marched with an overwhelming force to the relief of Wurtzburg. The town and citadel were already in the hands of the Swedes, and Maximilian of Bavaria was generally blamed (and not without cause, perhaps) for having, by his scruples, occasioned the loss of the bishopric. Commanded to avoid a battle, Tilly contented himself with checking the farther advance of the enemy; but he could save only a few of the towns from the impetuosity of the Swedes. Baffled in an attempt to reinforce the weak garrison of Hanau, which it was highly important to the Swedes to gain, he crossed the Maine, near Seligenstadt, and took the direction of the Bergstrasse, to protect the Palatinate from the conqueror.