TheNorthern War of 1655–1660, also known as theSecond Northern War,First Northern War orLittle Northern War, was fought betweenSweden and its adversaries thePolish–Lithuanian Commonwealth (1655–60), theTsardom of Russia (1656–58),Brandenburg-Prussia (1657–60), theHabsburg monarchy (1657–60) andDenmark–Norway (1657–58 and1658–60). TheDutch Republic waged an informaltrade war against Sweden and seized the colony ofNew Sweden in 1655, but was not a recognized part of the Polish–Danish alliance.

Second Northern War
Part of theNorthern Wars
From left to right: Battle of Warka Battle of Warsaw Unknown Polish–Swedish battle March Across the Belts Battle of the Sound Assault on Copenhagen
Date June 1655 – 23 April 1660 Location Denmark–Norway,Swedish Empire,Polish–Lithuanian Commonwealth,New Sweden andNew Netherland. Result See§ Peace Territorial changes Denmark–Norway cedesScania,Halland,Blekinge,Bohuslän andVen to Sweden. Poland–Lithuania recognizes Swedish sovereignty inLivonia and Swedish ownership ofEstonia andÖsel[2] Poland–Lithuania grants theDuchy of Prussia sovereign status. Dutch Republic acquiresNew Sweden.
Belligerents
Swedish Empire Brandenburg-Prussia (1656–57) Principality of Transylvania Cossack Hetmanate (1657)[1]  Wallachia Moldavia Susquehannock (1655) Swedish Lithuania (1655–57)[a]	Polish–Lithuanian Commonwealth Denmark–Norway (from 1657)  Habsburg Monarchy Tsardom of Russia (1656–58) Crimean Khanate Brandenburg-Prussia (1655–56, 1657–60) Duchy of Courland (1656–58)  Dutch Republic
Commanders and leaders
Charles X Gustav Arvid Wittenberg  Magnus de la Gardie Johan Risingh Janusz Radziwiłł  † Bogusław Radziwiłł   Frederick William I George II	John II Casimir Stefan Czarniecki Paweł Jan Sapieha Wincenty Korwin Gosiewski Frederick III Alexis of Russia Frederick William I Peter Stuyvesant
Casualties and losses
70,000 Swedes died[3][b]

In 1655,Charles X Gustav of Sweden invaded and occupied western Poland–Lithuania, the eastern half of which wasalready occupied by Russia. The rapid Swedish advance became known in Poland as theSwedish Deluge. TheGrand Duchy of Lithuaniabecame aSwedish protectorate, the Polish–Lithuanian regular armies surrendered and the Polish kingJohn II Casimir Vasa fled to theHabsburgs.Frederick William, Elector of Brandenburg andDuke of Prussia initially supported theestates inRoyal Prussia, butallied with Sweden in return for receiving the Duchy of Prussia as a Swedish fief. Exploiting the hurt religious feelings of theRoman Catholic population underProtestant occupation and organizing Polish–Lithuanian military leaders in theTyszowce Confederation, John II Casimir Vasa managed to regain ground in 1656. Russia took advantage of the Swedish setback,declared war on Sweden and pushed into Lithuania andSwedish Livonia.

Charles X Gustav then granted Frederick Williamfull sovereignty in the Duchy of Prussia in return for military aid, and in theTreaty of Radnot allied himself with theTransylvanianGeorge II Rákóczi who invaded Poland–Lithuania from the southeast. John II Vasa found an ally inLeopold I of Habsburg, whose armies crossed into Poland–Lithuania from the southwest. This triggeredFrederick III of Denmark's invasion of the Swedish mainland in early 1657, in an attempt to settle old scores from theTorstenson War while Sweden was busy elsewhere. Brandenburg left the alliance with Sweden when granted full sovereignty in the Duchy of Prussia by the Polish king in the treaties ofWehlau andBromberg.

Frederick III's war on Sweden gave Charles X Gustav a reason to abandon the Polish–Lithuanian deadlock and fight Denmark instead. After marching his army to the west and making adangerous crossing of the frozen straits in the winter of 1657/58, he surprised the unprepared Frederick III on the Danish isles and forced him into surrender. In theTreaty of Roskilde, Denmark had to abandon all Danish provinces in what is now Southern Sweden. The anti-Swedish allies meanwhile neutralized the Transylvanian army and Polish forces ravagedSwedish Pomerania.

In 1658 Charles X Gustav decided that instead of returning to the remaining Swedish strongholds in Poland–Lithuania, he would rather attack Denmark again. This time, Denmark withstood the attack and the anti-Swedish allies pursued Charles X Gustav toJutland and Swedish Pomerania. Throughout 1659, Sweden was defending her strongholds in Denmark and on the southern Baltic shore, while little was gained by the allies and a peace was negotiated. When Charles X Gustav died in February 1660, his successor settled for theTreaty of Oliva with Poland–Lithuania, the Habsburgs and Brandenburg in April and theTreaty of Copenhagen with Denmark in May. Sweden was to keep most of her gains from Roskilde, the Duchy of Prussia became a sovereign state, and otherwise, the parties largely returned to the status quo ante bellum. Sweden had already concluded a truce with Russia in 1658, which gave way to a final settlement in theTreaty of Cardis in 1661.

In English language, German, Russian and Scandinavian historiography, these conflicts were traditionally referred to asFirst Northern War.^[4] The term "Second Northern War", coined in Polish historiography (Druga Wojna Północna), has lately been increasingly adopted by German and English language historiography.^[4] Another ambiguous term referring to the Second Northern War is the Little Northern War,^[5] which however might also refer to the 1741–43 war. In Poland, the term"The Deluge" is also ambiguous, as it is sometimes used for a broader series of wars againstSweden,Brandenburg, Russia,Transylvania and theCossacks.

In 1648, thePeace of Westphalia had ended theThirty Years' War, during which theSwedish Empire emerged as a major European power. In theTorstenson War, a theater of the Thirty Years' War, Sweden had defeated the former Baltic great power Denmark-Norway. Sweden had been at peace with Russia since theTreaty of Stolbovo had ended theIngrian War in 1617.^[6] Sweden had remained in a state of war with thePolish–Lithuanian Commonwealth since thePolish–Swedish War (1626–29), which was concluded by the repeatedly renewed truce (Altmark,Stuhmsdorf).^[7]In 1651, an unsuccessful congress was organised inLübeck to mediate peace talks between Sweden and Poland-Lithuania.

On the other hand, the Commonwealth, under kingJohn II Casimir Vasa since 1648, experienced a crisis resulting both from theCossackKhmelnytsky Uprising in the southeast and from the paralysis of the administration due to the internal quarrels of the nobility, including feuds between the king and theLithuanian hetmanJanusz Radziwiłł and feuds among disagreeingsejmiks who had been able to stall each other's ambitions with theliberum veto since 1652. As a consequence, the Commonwealth lacked a sufficient defense.^[8]

In January 1654, the anti-Polishalliance of Pereiaslav was concluded between the rebellious Cossack HetmanBohdan Khmelnytsky andAlexis of Russia, who was in control of a well-equipped army that was undergoing modernization.^[9] In 1654, whenCharles X Gustav succeeded his cousinChristina on theSwedish throne,Russian forces were advancing into the unprotected Commonwealth, and by focusing on the northeast these drew close to the Swedish sphere of interest at theBaltic coast.^[10] Seeing the great success on the Russian side, Sweden also decided to intervene, among other reasons using the explanation that it was to protect the Protestant population in Poland. Having a close relationship with the Prince of Transylvania, Sweden had intentions to defeat Catholic Poland. Sweden also drew the risingCossack Hetmanate to its side that stood in strong opposition to the Polish government and promised military support if the Cossacks would break with the Russians.^[11]Bohdan Khmelnytsky sent an expedition headed by the Kiev colonel toHalychyna which soon turned back due to mutiny within its ranks. The leader of the Hetmanate did not participate in the actions due to poor health conditions.

Sweden, at that time an expansionist empire with an army designed to bemaintained 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. Also, Sweden was prevented from forming a Swedish–Polish alliance by the refusal of John II Casimir to drop his claims to the Swedish crown and the unwillingness of the Polish–Lithuanian nobility to make the territorial andpolitical concessions an alliance with Sweden would eventually cost,^[12][13] final negotiations inLübeck during February 1655 ended without a result.^[13] Thus, Sweden opted for a preemptive attack on the Polish–Lithuanian Commonwealth to occupy its yet available territories before the Russians.^[14]

Swedish forces entered Poland–Lithuania fromSwedish Pomerania in the west, andLivonia in the north.^[13][15] Thedivision on the western flank consisted of 13,650 men and 72 artillery pieces commanded byArvid Wittenberg who entered Poland on 21 July 1655 and another 12,700^[15] to 15,000^[13] commanded byCharles X Gustav who followed in August, while thedivision on the northern flank consisted of 7,200 men commanded byMagnus De la Gardie who had already seizedDünaburg with them on 12 July.^[15]

On the western front, Wittenberg was opposed by a Polish levy of 13,000 and an additional 1,400 peasant infantry. Aware of the military superiority of the well-trained Swedish army, the nobles ofGreater Poland surrendered to Wittenberg on 25 July inUjście after theBattle of Ujście, and then pledged loyalty to the Swedish king. Wittenberg established a garrison inPoznań (Posen).^[15]

On the northern front,Prince Janusz Radziwiłł signed theTreaty of Kėdainiai with Sweden on 17 August 1655, placing theGrand Duchy of Lithuania under Swedish protection. Though Radziwiłł had been negotiating with Sweden before, during his dispute with the Polish king, Kėdainiai provided a clause stipulating that the two parts of the Commonwealth, Poland and Lithuania, need not fight each other.^[15] Part of the Lithuanian army opposed the treaty however, forming a confederation led by the magnate and Polish–Lithuanian hetmanPaweł Jan Sapieha atWierzbołów.^[16]

On 24 August, Charles X Gustav joined Wittenberg's forces. The Polish kingJohn II Casimir leftWarsaw the same month to confront the Swedish army in the west, but after some skirmishes with the Swedish vanguard retreated southwards toKraków.^[15] On 8 September Charles X Gustav occupied Warsaw, then turned south to confront the retreating Polish king. The kings met at theBattle of Żarnów on 16 September, which like the next encounter at theBattle of Wojnicz on 3 October was a victory for Sweden. John II Casimir was exiled toSilesia while Kraków surrendered to Charles X Gustav on 19 October.^[17]

On 20 October, a second treaty was ratified atKėdainiai in the north. TheUnion of Kėdainiai unified Lithuania with Sweden, with Radziwiłł recognizing Charles X Gustav as Grand Duke of Lithuania.^[15] Over the following days, most of the Polish army surrendered to Sweden: on 26 October Koniecpolski surrendered with 5,385 men near Kraków, on 28 OctoberField Crown HetmanStanisław Lanckoroński andGreat Crown HetmanStanisław "Rewera" Potocki surrendered with 10,000 men, and on 31 October the levy ofMazovia surrendered after theBattle of Nowy Dwór.^[17]

Meanwhile, Russian and Cossack forces had occupied the east of the Polish–Lithuanian Commonwealth as far asLublin, with onlyLwow (Lviv, Lemberg) remaining under Polish–Lithuanian control.^[17] In late October, Charles X Gustav headed northwards and left Wittenberg in Kraków with a mobile force of 3,000 Swedish and 2,000 Polish troops, and an additional number scattered in garrisons, to control the southern part of the Swedish-occupied commonwealth.^[18]

In the north, theRoyal Prussian nobles concluded a defensive alliance with theElectorate of Brandenburg on 12 November in theTreaty of Rinsk, permitting Brandenburgian garrisons.Danzig (Gdansk),Thorn (Torun) andElbing (Elblag) had not participated in the treaty,^[7][19] with Thorn and Elbing surrendering to Sweden. In theTreaty of Königsberg on 17 January 1656,Frederick William, Elector of Brandenburg and Duke of Prussia, took theDuchy of Prussia, formerly a Polish fief, as a fief from Charles X Gustav. The Brandenburgian garrisons in Royal Prussia were withdrawn, and whenMarienburg (Malbork) surrendered in March, Danzig remained the only town not under Swedish control.^[19]

The rapid Swedish invasion and occupation of the Polish–Lithuanian territories became known in Poland as the "(Swedish) deluge."^{[20][21][22][23]}

The "deluge"^[20] and religious differences between the primarily Protestant Swedes and the primarily Catholic Poles,^[16][20] resulting in cases of maltreatment and murder of Catholic clergy and monks as well as cases of looting of Catholic churches and monasteries, gave rise to some partisan movements in the Swedish-occupied territory. A guerilla force attacked a small Swedish garrison atKoscian in October 1655 and killedFrederick of Hesse, brother-in-law of the Swedish king. The Pauline monasteryJasna Góra inCzęstochowasuccessfully resisted a Swedish siege throughout November 1655 to January 1656.^[16] On 20 November a manifesto was issued inOpole (Oppeln) calling for public resistance and the return of John II Casimir,^[19] and in December a peasant force tookNowy Sącz.^[16] On 29 December, the partisanTyszowce Confederation was constituted under participation of Lanckoroński and Potocki, and on 1 January 1656 John II Casimir returned from exile. Later in January,Stefan Czarniecki joined in, and by February most Polish soldiers who were in Swedish service since October 1655, had switched sides to that of the confederation.^[19]

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 theBattle of Gołąb in February 1656.^[18] Charles X Gustav then intended to take Lwow, but his advance was halted in theBattle of Zamość, when he was nearly encircled by the growing Polish–Lithuanian armies under Sapieha and Czarniecki, and barely escaped on 5 and 6 April breaking through Sapieha's lines during theBattle of Sandomierz at the cost of his artillery and baggage. A Swedish relief force underFrederick of Baden-Durlach was destroyed by Czarniecki on 7 April in theBattle of Warka.^[24] In the same month, John II Casimir with theLwów Oath proclaimedVirgin Mary queen of Poland, and promised to lift the burdens inflicted on the peasantry if he regained control.^[19]

On 25 June 1656,Charles X Gustav signed an alliance with Brandenburg: theTreaty of Marienburg grantedGreater Poland to Frederick William in return for military aid. While the Brandenburgian elector was free of Swedish vassalage in Greater Poland, he remained a Swedish vassal for theDuchy of Prussia.^[20][24] Brandenburgian garrisons then replaced the Swedish ones in Greater Poland, who went to reinforce Charles X Gustav's army.^[25] On 29 June however,Warsaw was stormed by John II Casimir, who had drawn up to Charles X Gustav with a force of 28,500 regulars and a noble levy of 18,000 to 20,000.^[24] Thereupon, Brandenburg actively participated in the war on the Swedish side, prompting John II Casimir Vasa to state that while his Tartars already had the Swedes for breakfast, he would now take Frederick William into custody, where neither sun nor moon would shine.^[20]

Already in May 1656,Alexis of Russia had declared war on Sweden, taking advantage of Charles being tied up in Poland, and Livonia,Estonia andIngria secured only by a Livonian army of 2,200 infantry and 400 dragoons,Magnus de la Gardie's 7,000 men in Prussia, and 6,933 men dispersed in garrisons along the Eastern Baltic coast. Alexis invaded Livonia in July with 35,000 men and tookDünaburg.^[26]

In late July, Danzig was reinforced by a Dutch garrison, and a combined Danish and Dutch fleet broke the naval blockage imposed on Danzig by Charles X Gustav.^[27] On 28–30 July, a combined Brandenburgian-Swedish army was able to defeat the Polish–Lithuanian army in theBattle of Warsaw,^[20][25] forcing John II Casimir to retreat toLublin. In August, Alexis' army took LivonianKokenhausen (Koknese), laid siege toRiga andDorpat (Tartu) and raided Estonia, Ingria andKexholm.^[28]

On 4 October, John II Casimir stormedŁęczyca in Greater Poland before heading for Royal Prussia,^[29] and on 8 October,Wincenty Korwin Gosiewski with 12,000 to 13,000 Lithuanian and Crimean Tartar cavalry overran a Brandenburgian-Swedish force in theBattle of Prostken inDucal Prussia.^[30] Gosiewski then ravaged Ducal Prussia, burning 13 towns and 250 villages, in a campaign that entered folklore because of the high death toll and the high number of captives deported to theCrimea.^[29]

On 22 October, Gosiewski was defeated by Swedish forces in theBattle of Filipów and turned to Lithuania.^[29] Also on 22 October, besieged Dorpat surrendered to Alexis, while theRussian siege of Swedish-held Riga was lifted.^[28] John II Casimir meanwhile tookBromberg (Bydgoszcz) andKonitz in Royal Prussia, and from 15 November 1656 until February 1657 stayed inDanzig, where aSwedish siege had to belifted due to Dutch intervention, just 55 kilometers away from Charles X Gustav's quarters inElbing.^[29]

In theTreaty of Labiau on 20 November, Charles X Gustav of Sweden granted Frederick William of Brandenburg full sovereignty in the Duchy of Prussia in return for a more active participation in the war.^[29][31] In theTreaty of Radnot on 6 December, Charles X Gustav promised to acceptGeorge II Rákóczi ofTransylvania as king of Poland and Grand Duke of Lithuania in return for his entrance into the war.^[29] Rákóczi entered the war in January 1657,^[29][31] crossing into the commonwealth with a force of 25,000 Transylvanian-Wallachian-Moldavian men and 20,000 Cossacks who reinforced Kraków before they met with Charles X Gustav, who had led a Swedish-Brandenburgian army southwards. The following month saw the Swedish-Brandenburg-Transylvanian-Romanian-Cossack forces play cat and mouse with the Polish–Lithuanian forces, moving about all of the commonwealth without any major engagements, except the capture ofBrest by Charles X Gustav in May, and the capture ofWarsaw by Rákóczi andGustaf Otto Stenbock on 17 June.^[29]

Due to internal conflicts within theCossacks there was practically no participation of theCossack Hetmanate in that war. Worn out from previous campaigns and requestingBohdan Khmelnytsky to break with Sweden, Alexis of Russia eventually signed theTruce of Vilna or Niemież with the Polish–Lithuanian Commonwealth, and did not engage the Swedish army in any major battle throughout 1657 even though he still reinforced his armies in Livonia. On 18 June, a Swedish force defeated a Russian army of 8,000 men commanded by Matvey V. Sheremetev in theBattle of Walk, however, a month later it was defeated by the Russiansnear Gdov, after that the actions were in the nature of mutual raids. In early 1658, Sweden and Russia agreed on a truce,^[28] resulting in theTreaty of Valiesar (Vallisaare, 1658) and theTreaty of Kardis (Kärde, 1661). TheRussian war with Poland–Lithuania on the other hand resumed in 1658.^[32]

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 withFerdinand III of Habsburg inVienna,^[20][33] 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 successorLeopold I of Habsburg,^[31][33] 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 theAustrian army entered the Polish–Lithuanian Commonwealth from the south,^[33] immediately stabilizing the situation in southern Poland byconquering Kraków,^[31] while Denmark attacked SwedishBremen-Verden and turned toJämtland andVästergötland in July.^[33]

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 intoUkraine he was encircled and forced to capitulate, with the rest of the Transylvanian army defeated by the Tartars.^[33]

Brandenburg changed sides in return for Polish withdrawal of claims toDucal Prussia, declaring Frederick William the sole sovereign in the Duchy with the treaties ofWehlau on 19 September andBromberg on 6 November.^[31][33] In addition, the aforementioned treaties secured Brandenburg theLands of Lauenburg and Bütow at the border ofBrandenburgian Pomerania, while theBishopric of Ermeland was returned to Poland.^[31]

The attack ofFrederick III of Denmark in June 1657, aimed at regainingthe territories lost in 1645, provided an opportunity for Charles X Gustav to abandon the unfortunate Polish–Lithuanian battlefields. With 9,950 horse and 2,800 foot, he marched throughPomerania andMecklenburg. InHolstein, the Swedish force was split withCarl Gustaf Wrangel heading west to clearBremen-Verden and Charles X Gustav heading north to clearJutland.^[33] When these aims were achieved, Charles X Gustav in September moved to the Swedish port ofWismar and ordered his navy into the inconclusive Battle of Møn.^[34]

Meanwhile, Polish forces led by generalStefan Czarniecki ravaged southernSwedish Pomerania, and destroyed and plunderedPasewalk,Gartz (Oder) andPenkun.^[35] The Habsburg and Brandenburg allies however were reluctant to join Czarniecki, and against John II Casimir's wish decided against taking the war to theHoly Roman Empire fearing the start of a newThirty Years' War.^[34]

The harsh winter of 1657/58 had forced the Dano-Norwegian fleet to stay in port, and theGreat andLittle Belts separating the Danish isles from the mainland were frozen. After enteringJutland from the south, a Swedish army of 7,000 veterans undertook theMarch across the Belts; on 9 February 1658, the Little Belt was crossed and the islandFunen (Fyn) captured within a few days, and soon thereafterLangeland,Lolland andFalster. On 25 February, the Swedish army continued across the Great Belt toZealand where the Danish capitalCopenhagen is located. Although only 5,000 men made it across the belts, the Swedish attack was completely unexpected; Frederick III was compelled to surrender and signed the disadvantageousTreaty of Roskilde on 26 February 1658.^[34]

Sweden had won its most prestigious victory, and Denmark had suffered its most costly defeat.^[36] Denmark was forced to yield the provinces ofScania,Halland,Blekinge and the island ofBornholm. Halland had already been under Swedish control since the signing of theTreaty of Brömsebro in 1645, but they now became Swedish territory indefinitely. Denmark also had to surrender the Norwegian provinceTrøndelag to Sweden.

Yet, Swedish-held territory in Poland had been reduced to some towns inRoyal Prussia, most notablyElbing,Marienburg andThorn. With Transylvania neutralized and Brandenburg defected, Charles X Gustav's position in the region was not strong enough to force his stated aim, the permanent gain of Royal Prussia. He was further pressed militarily when an Austro-Polish army laid siege to Thorn in July 1658, and diplomatically when he was urged byFrance to settle.^[34] France was unwilling to intervene militarily, and Sweden could not afford to violate thePeace of Westphalia by attacking the Habsburg and Brandenburgian possessions in theHoly Roman Empire, which would likely have driven several Germans into the anti-Swedish alliance. Thus, Charles X Gustav opted to instead attack Denmark again.^[37]

When the Danes stalled and prolonged the fulfillment of some provisions of the Treaty of Roskilde by postponing payments and not blocking foreign fleets from access to the Baltic Sea, and with half of the 2,000 Danish soldiers that were obliged by Roskilde to enter Swedish service deserting, the Swedish king embarked fromKiel with a force of 10,000 men on 16 August. While everyone expected him to head for Royal Prussia, he disembarked on Zealand on 17 August, and headed forCopenhagen,^[37] which was defended by 10,650 Danes and 2,000 Dutch. This time however, the town did not surrender, and a long siege ensued. When Swedish forces tookKronborg in September, they controlled both sides of theØresund, yet in November a Dutch fleet broke the Swedish naval blockade of Copenhagen in theBattle of the Sound.^[38]

Meanwhile, the anti-Swedish alliance had deployed an army to Denmark, to confront Charles X Gustav with a force of 14,500 Brandenburgers commanded byFrederick William, 10,600 Austrians commanded byRaimondo Montecuccoli, and 4,500 Poles commanded by Czarniecki. By January 1659, the allied forces stood atFredriksodde,Kolding andAls. Charles X Gustav then tried a decisive assault on Copenhagen on 21 and 22 February, but was repelled.^[38]

In 1659, the war was characterized by Swedish forces defending their strongholds on the southern Baltic coast against allied assaults. A combined force of 17,000 Austrians and 13,000 Brandenburgers^[38] led by general Jean-Louis Raduit de Souches invadedSwedish Pomerania, took and burnedGreifenhagen, tookWollin island andDamm, besiegedStettin andGreifswald without success, but tookDemmin on 9 November. Counterattacks were mounted by generalMüller von der Lühnen, who lifted the siege laid on Greifswald by the Brandenburgian prince-elector, and major generalPaul Wirtz, who from besieged Stettin managed to capture the Brandenburgian ammunition depot at Curau and took it toStralsund. The Brandenburgians withdrew ravaging the countryside while retreating.^[35]

In the occupied and annexed Danish provinces, guerilla movements pressed Swedish garrisons. After an uprising,Norwegians took Trondheim in late 1658. InScania andZealand, the "snaphaner" led byLorenz Tuxen andSvend Poulsen ("Gøngehøvdingen") ambushed Swedish forces. The Swedish garrison ofBornholm wasforced to surrender to Danish insurgents, with the commander killed.^[39]

In Royal Prussia (Eastern Pomerania in contemporary Poland),Thorn had fallen already in December 1658, butElbing andMarienwerder withstood. On 24 November, Sweden had to abandonFunen andLangeland after the defeat in theBattle of Nyborg. In January 1660, Sweden lost theLivonian fortressMitau.^[38]

Meanwhile, conflicts arose within the anti-Swedish alliance between the Habsburgs and Poland–Lithuania when the Habsburgs demanded ever more contributions while not showing the war efforts Poland–Lithuania had expected. With theRusso-Polish War ongoing, most Polish–Lithuanian forces were tied up inUkraine. England, France and theDutch Republic had agreed on a petition in theFirst Concert of the Hague, urging Sweden to settle for peace with Denmark on the terms of Roskilde, and peace talks mediated by France were taking place throughout 1659.^[38]

The colony ofNew Sweden lay along theDelaware River, a territory claimed but not settled by DutchNew Netherland. The Swedish colonists were the preferred trading partners of theSusquehannock, who at that time were the most powerful indigenous group in the Susquehanna River valley and rivals to theIroquois Confederacy further north. The Iroquois in turn were allies of the Dutch.

The Dutch–Polish alliance in Europe left its mark in New Netherland. Among the small Polish community inNew Amsterdam wasDaniel Liczko, a military officer who took part in an expedition to erect a fort in Swedish territory in 1651. Director-GeneralPeter Stuyvesant named the outpostFort Casimir after the Polish king,^[40] but it was captured and renamed Fort Trinity (Swedish:Trefaldigheten) by Swedish governorJohan Risingh in May 1654. Following the outbreak of the Second Northern War in Europe, Stuyvesant retaliated. In the summer of 1655, he dispatched most of the colonial garrison to the Delaware River and led a squadron of ships to attack New Sweden. The Dutch recaptured Fort Trinity on 11 September and besieged the Swedish capital atFort Christina for ten days before Risingh surrendered on 15 September.^[41][42] This effectively marked the end of New Sweden, but for a time the Swedish and Finnish settlers continued to enjoy local autonomy with their own militia, religion,court and lands.^[43] Sweden had no further territorial presence in the Americas until the acquisition ofSaint Barthélemy from France in 1784.

On 15 September, while the bulk of the Dutch garrison was still in New Sweden, 500Munsee occupied New Amsterdam in what in known as thePeach War. No bloodshed occurred until the Dutch opened fire as the Munsee were preparing to depart. In response the Munsee attackedPavonia andStaten Island. Stuyvesant later reported 40 deaths and 100 captives taken. Many Dutch settlers from outlying farms took refuge atFort Amsterdam.^[44][45]

The cause of the Peach War has been the subject of debate. The armed protest and raids may have been triggered by the murder of a Munsee woman who was stealing peaches from the orchard of a Dutch colonist. Many historians, however, have speculated that the Peach War was orchestrated by the Susquehannock in response to the Dutch attack on New Sweden.^[46][47]

After renegotiating land rights and securing the release of the hostages, the Dutch resettled most of their abandoned territory and constructed several additional fortifications. Stuyvesant decreed that "like our neighbors ofNew England," the New Netherland colonists must now "concentrate themselves... in the form of towns, villages and hamlets, so that they may be the more effectually protected" against future attacks.^[48][49] Notably, theStaten Island colony was not reoccupied for several years. Itspatroon wasCornelis Melyn, former chairman of theCouncil of Eight Men and a political rival of Stuyvesant; he had been imprisoned without trial earlier in the year. Melyn and his family defected toEnglish New Haven soon after his release.

Charles X Gustav fell ill in early 1660 and died on 23 February of that year. With his death, one of the major obstacles to peace was gone and theTreaty of Oliva was signed on 23 April. Sweden was accepted as sovereign inSwedish Livonia, Brandenburg was accepted as sovereign inDucal Prussia, and John II Casimir withdrew his claims to the Swedish throne, though he was to retain the title for life. All occupied territories were restored to their pre-war sovereigns.^[32]

However, Denmark was not keen on peace after its recent successes and witnessing the weakness of the Swedish efforts. The Dutch Republic withdrew its blockade but was soon convinced by Denmark to support them again. France and England intervened for Sweden and the situation again teetered on the edge of a major conflict. However, the Danish statesmanHannibal Sehested negotiated a peace treaty without any direct involvement by foreign powers. The conflict was resolved with theTreaty of Copenhagen (1660). Sweden returnedBornholm andTrøndelag to Denmark.^[32] The treaty of 1660 established political borders between Denmark, Sweden and Norway which have lasted to the present day, and secured the Swedishdominium maris baltici.

Russia, still engaged in theRusso-Polish War (1654–1667), settled its dispute with Sweden in theTreaty of Cardis, which restored Russian-occupied Swedish territory to Sweden.^[32]

• Treaty of Königsberg: Sweden and Brandenburg–Prussia (1656, superseded by Bromberg and Oliva)
• Treaty of Bromberg: Brandenburg–Prussia and Poland–Lithuania
• Treaty of Roskilde: Sweden and Denmark-Norway (1658, superseded by Copenhagen)
• Treaty of Oliva: Sweden and Brandenburg–Prussia, Austria and Poland–Lithuania (1660)
• Treaty of Copenhagen: Sweden and Denmark–Norway (1660)
• Treaty of Cardis: Sweden and Russia (1661)

• Great Northern War
• List of Prussian wars
• List of Swedish wars
• Polish–Swedish wars
• Second Northern War and Norway
• Deluge (history)

•   Media related toSecond Northern War at Wikimedia Commons