Meantime, the imperial generals, deficient both in troops and money, found themselves reduced to the disagreeable alternative of losing sight either of the King of Sweden, or of the Estates of the empire, since with a divided force they were not a match for either.
The movements of the Protestants called their attention to the interior of the empire, while the progress of the king in Brandenburg, by threatening the hereditary possessions of Austria, required them to turn their arms to that quarter. After the conquest of Frankfort, the king had advanced upon Landsberg on the Warta, and Tilly, after a fruitless attempt to relieve it, had again returned to Magdeburg, to prosecute with vigour the siege of that town.
The rich archbishopric, of which Magdeburg was the capital, had long been in the possession of princes of the house of Brandenburg, who introduced the Protestant religion into the province. Christian William, the last administrator, had, by his alliance with Denmark, incurred the ban of the empire, on which account the chapter, to avoid the Emperor's displeasure, had formally deposed him.
In his place they had elected Prince John Augustus, the second son of the Elector of Saxony, whom the Emperor rejected, in order to confer the archbishopric on his son Leopold.
The Elector of Saxony complained ineffectually to the imperial court;but Christian William of Brandenburg took more active measures.
Relying on the attachment of the magistracy and inhabitants of Brandenburg, and excited by chimerical hopes, he thought himself able to surmount all the obstacles which the vote of the chapter, the competition of two powerful rivals, and the Edict of Restitution opposed to his restoration.
He went to Sweden, and, by the promise of a diversion in Germany, sought to obtain assistance from Gustavus. He was dismissed by that monarch not without hopes of effectual protection, but with the advice to act with caution.
Scarcely had Christian William been informed of the landing of his protector in Pomerania, than he entered Magdeburg in disguise. Appearing suddenly in the town council, he reminded the magistrates of the ravages which both town and country had suffered from the imperial troops, of the pernicious designs of Ferdinand, and the danger of the Protestant church. He then informed them that the moment of deliverance was at hand, and that Gustavus Adolphus offered them his alliance and assistance. Magdeburg, one of the most flourishing towns in Germany, enjoyed under the government of its magistrates a republican *******, which inspired its citizens with a brave heroism. Of this they had already given proofs, in the bold defence of their rights against Wallenstein, who, tempted by their wealth, made on them the most extravagant demands.
Their territory had been given up to the fury of his troops, though Magdeburg itself had escaped his vengeance. It was not difficult, therefore, for the Administrator to gain the concurrence of men in whose minds the rememberance of these outrages was still recent.
An alliance was formed between the city and the Swedish king, by which Magdeburg granted to the king a free passage through its gates and territories, with liberty of enlisting soldiers within its boundaries, and on the other hand, obtained promises of effectual protection for its religion and its privileges.
The Administrator immediately collected troops and commenced hostilities, before Gustavus Adolphus was near enough to co-operate with him. He defeated some imperial detachments in the neighbourhood, made a few conquests, and even surprised Halle. But the approach of an imperial army obliged him to retreat hastily, and not without loss, to Magdeburg. Gustavus Adolphus, though displeased with his premature measures, sent Dietrich Falkenberg, an experienced officer, to direct the Administrator's military operations, and to assist him with his counsel. Falkenberg was named by the magistrates governor of the town during the war. The Prince's army was daily augmented by recruits from the neighbouring towns; and he was able for some months to maintain a petty warfare with success.
At length Count Pappenheim, having brought his expedition against the Duke of Saxe-Lauenburg to a close, approached the town.
Driving the troops of the Administrator from their entrenchments, he cut off his communication with Saxony, and closely invested the place.
He was soon followed by Tilly, who haughtily summoned the Elector forthwith to comply with the Edict of Restitution, to submit to the Emperor's orders, and surrender Magdeburg. The Prince's answer was spirited and resolute, and obliged Tilly at once to have recourse to arms.
In the meanwhile, the siege was prolonged, by the progress of the King of Sweden, which called the Austrian general from before the place;and the jealousy of the officers, who conducted the operations in his absence, delayed, for some months, the fall of Magdeburg. On the 30th March 1631, Tilly returned, to push the siege with vigour.
The outworks were soon carried, and Falkenberg, after withdrawing the garrisons from the points which he could no longer hold, destroyed the bridge over the Elbe. As his troops were barely sufficient to defend the extensive fortifications, the suburbs of Sudenburg and Neustadt were abandoned to the enemy, who immediately laid them in ashes.
Pappenheim, now separated from Tilly, crossed the Elbe at Schonenbeck, and attacked the town from the opposite side.
