Austro–Brandenburgian–Polish alliance, Danish campaigns in Sweden

Like Sweden, John II Casimir was also looking for allies to break the deadlock of the war. On 1 December 1656, he signed an alliance with Ferdinand III of Habsburg in Vienna, essentially a declaration of Ferdinand III's intend to mediate a peace rather than provide military aid, which did not come into effect until Ferdinand's death on 2 April 1657. The treaty was however renewed and amended on 27 May by Ferdinand's successor Leopold I of Habsburg, who agreed in Vienna to provide John II Casimir with 12,000 troops maintained at Polish expense; in return, Leopold received Kraków and Posen in pawn. Receiving the news, Frederick III of Denmark promptly declared war on Sweden, and by June the Austrian Flag of Archduchy of Austria The Archduchy of Austria was a major principality of the Holy Roman Empire and the nucleus of the Habsburg monarchy. With its capital at Vienna, the archduchy was centered at the Empire's southeastern periphery. The archduchy's history as an imperial state ended with the dissolution of the Holy Roman Empire in 1806. It was replaced with the Lower and Upper Austria crown lands of the Austrian Empire.Austrian army entered the Polish–Lithuanian Commonwealth from the south, immediatetly stabilizing the situation in southern Poland, while Denmark attacked Swedish Bremen-Verden and turned to Jämtland and Västergötland in July.

When Charles X Gustav left the Commonwealth and headed westwards for an anti-Danish counterstrike, the Swedish–Brandenburgian–Transylvanian alliance broke apart. Rákóczi of Transylvania was unable to withstand the combined Austrian and Polish–Lithuanian forces without Swedish support, and after a pursuit into Ukraine he was encircled and forced to capitulate, with the rest of the Transylvanian army defeated by the Tartars.

Brandenburg changed sides in return for Polish withdrawal of claims to Ducal Prussia, declaring Frederick William the sole sovereign in the Duchy with the treaties of Wehlau on 19 September and Bromberg on 6 November. In addition, the aforementioned treaties secured Brandenburg the Lands of Lauenburg and Bütow at the border of Brandenburgian Pomerania, while the Bishopric of Ermeland was returned to Poland.

Territorial changes following the Treaty of Wehlau-Bromberg, compared to the pre-war situation (1654) and the treaties of Königsberg (January 1656) and Labiau (November 1656)

( Click image to enlarge)

Outline of the Second Northern War (1655–1660)

HISTORIC BATTLES

Second Northern War (1655–1660)

The Second Northern War (also First or Little Northern War) was fought between Sweden and its adversaries the Polish–Lithuanian Commonwealth, Russia, Brandenburg-Prussia, the Habsburg Monarchy and Denmark–Norway. The Dutch Republic often intervened against Sweden. View Historic Battle »

Prelude: Sweden, at that time an expansionist empire with an army designed to be maintained by the revenues of occupied territory, was conscious that a direct attack on her main adversary Russia could well result in a Dano-Polish–Russian alliance.

Swedish campaigns in the Polish–Lithuanian Commonwealth: On the western front, Wittenberg was opposed by a Polish levy of 13,000 and an additional 1,400 peasant infantry.

Occupation of Poland-Lithuania and the Brandenburgian intervention: In the north, the Royal Prussian nobles concluded a defensive alliance with the Electorate of Brandenburg on 12 November in the Treaty of Rinsk, permitting Brandenburgian garrisons.

Polish–Lithuanian recovery: Charles X Gustav, with a force of 11,000 horse, reacted by pursuing Czarniecki's force of 2,400 men, confronting and defeating him in the Battle of Gołąb in February 1656.

Brandenburgian-Swedish alliance and Russia's war on Sweden: On 25 June 1656, Charles X Gustav signed an alliance with Brandenburg: the Treaty of Marienburg granted Greater Poland to Frederick William in return for military aid.

Swedish–Brandenburgian–Transylvanian–Romanian alliance and the truces with Russia: Rákóczi entered the war in January 1657, crossing into the commonwealth with a force of 25,000 Transylvanian-Wallachian-Moldavian men and 20,000 Cossacks who broke the Polish siege of Kraków before they met with Charles X Gustav, who had led a Swedish-Brandenburgian army southwards.

Austro–Brandenburgian–Polish alliance, Danish campaigns in Sweden: On 1 December 1656, he signed an alliance with Ferdinand III of Habsburg in Vienna, essentially a declaration of Ferdinand III's intend to mediate a peace rather than provide military aid, which did not come into effect until Ferdinand's death on 2 April 1657.

Denmark and Pomerania: The attack of Frederick III of Denmark in June 1657, aimed at regaining the territories lost in 1645, provided an opportunity for Charles X Gustav to abandon the unfortunate Polish–Lithuanian battlefields.

Sweden entrenched: In 1659, the war was characterized by Swedish forces defending their strongholds on the southern Baltic coast against allied assaults.

New Sweden: The Dutch moved an army to the Delaware River in the summer of 1655, easily capturing Fort Trinity and Fort Christina.

Peace: Russia, still engaged in the Russo-Polish War (1654–67), settled her dispute with Sweden in the Treaty of Kardis, which restored Russian-occupied Swedish territory to Sweden.

HISTORY

Second Northern War (1655–1660)

The Second Northern War (also First or Little Northern War) was fought between Sweden and its adversaries the Polish–Lithuanian Commonwealth, Russia, Brandenburg-Prussia, the Habsburg Monarchy and Denmark–Norway. The Dutch Republic often intervened against Sweden.