In vain was this new demand, which could be granted only at the expense of two princes of the empire, actively resisted in the Imperial Council;in vain did the Spaniards, who had long been offended by his pride, oppose his elevation. The powerful support which Wallenstein had purchased from the imperial councillors prevailed, and Ferdinand was determined, at whatever cost, to secure the devotion of so indispensable a minister.
For a slight offence, one of the oldest German houses was expelled from their hereditary dominions, that a creature of the Emperor might be enriched by their spoils (1628).
Wallenstein now began to assume the title of generalissimo of the Emperor by sea and land. Wismar was taken, and a firm footing gained on the Baltic.
Ships were required from Poland and the Hanse towns to carry the war to the other side of the Baltic; to pursue the Danes into the heart of their own country, and to compel them to a peace which might prepare the way to more important conquests. The communication between the Lower German States and the Northern powers would be broken, could the Emperor place himself between them, and encompass Germany, from the Adriatic to the Sound, (the intervening kingdom of Poland being already dependent on him,) with an unbroken line of territory.
If such was the Emperor's plan, Wallenstein had a peculiar interest in its execution. These possessions on the Baltic should, he intended, form the first foundation of a power, which had long been the object of his ambition, and which should enable him to throw off his dependence on the Emperor.
To effect this object, it was of extreme importance to gain possession of Stralsund, a town on the Baltic. Its excellent harbour, and the short passage from it to the Swedish and Danish coasts, peculiarly fitted it for a naval station in a war with these powers.
This town, the sixth of the Hanseatic League, enjoyed great privileges under the Duke of Pomerania, and totally independent of Denmark, had taken no share in the war. But neither its neutrality, nor its privileges, could protect it against the encroachments of Wallenstein, when he had once cast a longing look upon it.
The request he made, that Stralsund should receive an imperial garrison, had been firmly and honourably rejected by the magistracy, who also refused his cunningly demanded permission to march his troops through the town, Wallenstein, therefore, now proposed to besiege it.
The independence of Stralsund, as securing the free navigation of the Baltic, was equally important to the two Northern kings. A common danger overcame at last the private jealousies which had long divided these princes.
In a treaty concluded at Copenhagen in 1628, they bound themselves to assist Stralsund with their combined force, and to oppose in common every foreign power which should appear in the Baltic with hostile views.
Christian IV. also threw a sufficient garrison into Stralsund, and by his personal presence animated the courage of the citizens.
Some ships of war which Sigismund, King of Poland, had sent to the assistance of the imperial general, were sunk by the Danish fleet;and as Lubeck refused him the use of its shipping, this imperial generalissimo of the sea had not even ships enough to blockade this single harbour.
Nothing could appear more adventurous than to attempt the conquest of a strongly fortified seaport without first blockading its harbour.
Wallenstein, however, who as yet had never experienced a check, wished to conquer nature itself, and to perform impossibilities. Stralsund, open to the sea, continued to be supplied with provisions and reinforcements;yet Wallenstein maintained his blockade on the land side, and endeavoured, by boasting menaces, to supply his want of real strength.
"I will take this town," said he, "though it were fastened by a chain to the heavens." The Emperor himself, who might have cause to regret an enterprise which promised no very glorious result, joyfully availed himself of the apparent submission and acceptable propositions of the inhabitants, to order the general to retire from the town. Wallenstein despised the command, and continued to harass the besieged by incessant assaults.
As the Danish garrison, already much reduced, was unequal to the fatigues of this prolonged defence, and the king was unable to detach any further troops to their support, Stralsund, with Christian's consent, threw itself under the protection of the King of Sweden. The Danish commander left the town to make way for a Swedish governor, who gloriously defended it.
Here Wallenstein's good fortune forsook him; and, for the first time, his pride experienced the humiliation of relinquishing his prey, after the loss of many months and of 12,000 men. The necessity to which he reduced the town of applying for protection to Sweden, laid the foundation of a close alliance between Gustavus Adolphus and Stralsund, which greatly facilitated the entrance of the Swedes into Germany.
Hitherto invariable success had attended the arms of the Emperor and the League, and Christian IV., defeated in Germany, had sought refuge in his own islands; but the Baltic checked the further progress of the conquerors. The want of ships not only stopped the pursuit of the king, but endangered their previous acquisitions. The union of the two northern monarchs was most to be dreaded, because, so long as it lasted, it effectually prevented the Emperor and his general from acquiring a footing on the Baltic, or effecting a landing in Sweden. But if they could succeed in dissolving this union, and especially securing the friendship of the Danish king, they might hope to overpower the insulated force of Sweden.
