Dano - Swedish War ( 1658 – 60 ) The Dano - Swedish War of 1658 – 60 ( , , ) was a war between Denmark – Norway and Sweden . It was a continuation of an earlier conflict between the two belligerents which had ended just months earlier , after Sweden and Denmark brokered a peace agreement in Roskilde in 1658 . In the aftermath of that conflict , the Swedish king Charles X Gustav desired to add the province of Royal Prussia in Poland to the Swedish realm , but his position in the region was not strong enough with the opposition of Brandenburg and Austria . However , the Danes stalled and prolonged the fulfillment of some provisions of the earlier peace ; the Swedish king decided to use this as a pretext to attack with an ambitious goal : to vanquish Denmark as a sovereign state and raze the capital of Copenhagen . A quick and decisive defeat of Denmark was however only seen as a means to a greater end . The long - term goal was to wage war in Europe without fearing Danish interference . The Swedish army surrounded Copenhagen , hoping to starve it into submission . This failed when the Dutch Republic joined the conflict on the Danish side and a reinforcing fleet managed to smash its way through the Swedish naval forces in Øresund . Charles then tried a decisive assault on the city , hoping to conquer it and win the war ; this plan likewise failed . Brandenburg , Poland and Austria then also joined the war against the Swedes . Charles X fell ill in early 1660 and died in February of that year . With the death of the Swedish king , one of the major obstacles to peace was gone and the Treaty of Oliva was signed with the Allies ( the Poland , Austria and Brandenburg ) . However , the Danes were not keen on peace after their recent successes and witnessing the weakness of the Swedish efforts . The Dutch retracted their blockade , but were soon convinced by the Danes to support them again . The French and English intervened for the Swedish and the situation was again teetering on the edge of a major conflict . However , the Danish statesman Hannibal Sehested negotiated a peace treaty without any direct involvement by foreign powers and the conflict was resolved with the Treaty of Copenhagen , where Sweden was forced to return Bornholm to Denmark and Trøndelag to Norway . The treaty of 1660 established political borders between Denmark , Sweden and Norway which have lasted to the present day . Background . Charles X of Sweden had concluded the earlier war with Denmark with a stunning victory by succeeding in the bold March across the Belts . Denmark - Norway had been forced into a humiliating peace in the Treaty of Roskilde in which Denmark had to cede Scania , Halland and Blekinge on the Scandinavian Peninsula and the island of Bornholm , and Norway lost the provinces of Båhuslen and Trøndelag . Europe was stunned by the quick victory , and Charles proudly publicized his accomplishments . However , peace meant new problems . In the peace treaty of Roskilde , Denmark was obliged to supply the Swedish army with provisions until May 1658 , but soon thereafter the army would need to be moved . The Swedish king knew that the army would not be able to be supplied in Sweden for long , and disbanding it was not desirable with the Poles eager to revenge the 1655 invasion of Poland . Sweden was not in want of enemies to attack : campaigns in Livonia and Estonia were considered , but were rejected due to supply problems . The Swedish King maintained that his main goal was to invade Royal Prussia , but he also wanted to punish Frederick William of Brandenburg - Prussia . The many enemies in continental Europe , among them Poland and a hostile Dutch would make this a difficult endeavor however . A new attack on Prussia would also see little international support , France was already urging peace . The surprising Swedish solution to this dilemma would be to return to Denmark in an attempt to finish the job . When the Danish stalled and prolonged the fulfillment of some provisions of the earlier peace treaty the Swedish king decided to use this as a pretext to attack with a breathtaking goal : to vanquish Denmark as a sovereign state , raze the capital of Copenhagen and divide the country into four administrative regions . This would allow Sweden to control the Baltic Sea and bring in large customs revenues . However , even this ambitious goal was just to be stepping stone towards the ultimate plan of a quick conquest of Denmark so that the Swedes could wage a campaign in Europe without risking Danish interference . Events . In June 1658 it was decided that the Swedish forces would attack . On August 6 , 1658 a fleet of 70 ships with 5 , 700 men and 18 pieces of light artillery embarked upon a journey to Denmark . Since the previous war , Jylland was still occupied by Swedish troops and there were troops on Fyn . In addition to this , Field Marshal Gustav Otto Stenbock had assembled reinforcements in Scania in Southern Sweden . The plan was for the Swedish army to march on Copenhagen . Siege of Copenhagen . On August 11 , 1658 Charles X and his forces reached Valby hill ( current day Frederiksberg ) from where they could overlook the Danish capital . His arrival was expected and the Danish king Frederick III had already ordered every building outside the city wall s burnt , even though it had housed a third of the population of the city . That same day the city gate s were closed and would not open again for another 22 months . A Swedish fleet of 28 ships blocked the harbor , preventing resupply by sea . The siege had begun . When the Swedish king arrived to find half the city in flames and the Danes willing to put up a fight he had a difficult decision to make ; whether to press forward immediately or to lay siege on the city and try to starve it out . His advisers were divided on the issue , and the king ultimately decided on the latter route . The wisdom of this decision has been questioned , since the Danish defenses were in poor shape initially . However , the population of Copenhagen rallied behind Frederick III , and the walls , moats and other defensive structures of the city were quickly improved . A large number of cannons were brought into the city from ships anchored in the harbor and placed along likely attack routes . The city also had plenty of defensive materiel : of lead , 4 , 000 musket s , and a staggering of slow match . The Swedish siege force consisted of 11 brigades and 16 squadrons comprising 4 , 000 infantry , 2 , 000 cavalry and 50 cannons . The Swedes took the outer defensive perimeter , built in 1625 by Christian IV , which had fallen into disrepair . It was hastily repaired and artillery was brought to bear on the city . The Danes would not let the Swedish attack go uncontested , and made several counter - attacks . On August 23 , 1658 almost 3 , 000 students , sailors and soldiers staged a surprise sortie through a hidden passage in the wall , destroying fortification s under construction and capturing three cannons . Over 200 heated shot a day were hurled into the city , and several large howitzer s were brought to bombard the Danish capital , including the 300 - pounder " Eric Hansson " , earlier used in the siege of Krakow . But the citizens of Copenhagen proved to be resilient and endured the constant barrage . Kronborg captured . In a 1649 treaty the Dutch had pledged to defend Denmark against unprovoked aggression , and from a Swedish point of view it was essential to establish naval supremacy in Øresund to keep the Dutch out should they decide to intervene in the conflict . Kronborg Castle sat near the narrowest part of Øresund , a sound only four kilometres wide , which gave the castle a supreme strategic importance . Frederick III had appointed the colonel Poul Beenfeldt commander of the castle and ordered him to defend it at all costs . Should he fail in that , Kronborg was to be blown up to prevent the Swedes from using it . On August 16 the Swedes arrived at Helsingør , took shelter in the city and started bombarding the castle with artillery . The Danes returned the fire , attempting to set the city on fire . They managed to destroy a dozen houses , but the fire did not spread enough to cause a conflagration . Danish artillery rained continually on the Swedish soldiers . However , the Swedish force still managed to advance , taking the outer line of defenses . The mood in the castle darkened , and Beenfeldt ' s courage wavered . The Swedish commander Karl Gustav Wrangel resorted to subterfuge and spread the rumor that Copenhagen had fallen and the Swedish soldiers started a false celebration . Discouraged and demoralized , the Danes capitulated . The loss of Kronborg was a blow for the Danish ; 77 captured cannons were quickly put to use in the siege and with the castle in Swedish hands , it was believed that the Dutch would have a difficult time to come to aid . Battle of the Sound . Despite Swedish hopes that the Dutch would not enter the conflict , they honored their 1649 treaty by sending a 45 - ship relief fleet . On October 7 , 1658 the Dutch fleet set sail from Vlie . Two weeks later , on October 22 , it anchored northwest of Helsingør , unable to proceed for six days due to wind conditions . Wrangel suggested the Swedes should attack , but Charles X still wanted to avoid provoking the Dutch . On October 29 at eight o ' clock in the morning , a shot was heard from the Dutch flag ship . It was the signal to advance and smash the Swedish line . The Dutch fleet was divided into three squadrons . Vice Admiral Witte de With on the 54 - gun ship " Brederod " and his 11 - ship squadron led the charge , followed by Admiral Jacob van Wassenaer Obdam on the 72 - gun " Eendracht " with 13 ships in the squadron . The last squadron , led by Pieter Floriszoon had 11 ships . In total , the Dutch fleet consisted of 45 ships with 1 , 838 cannons and 4 , 000 sailors . Following the warships , many transports with large quantities of food and supplies as well as 28 regiments of experienced soldiers followed , in total 2 300 men . Standing against them was a Swedish navy force consisting of 43 ships , with 1 , 605 cannons and 4 , 055 sailors . The Swedes also had great hopes that the coastal artillery of Kronborg would inflict great damage . Charles personally fired the first hostile shot from Kronborg , but it fell short ; the Dutch had wisely chosen to sail closer to the Swedish side , where there were fewer land - based guns to contend with . The Swedish force had more guns , but the Dutch had the advantage of the wind . In the narrow straits of Øresund , nearly a hundred warships now battled . The engagement was confusing for both sides , and the view was soon obscured by gunpowder smoke . Many ships on both sides were badly damaged , and around 2 , 000 men killed or wounded . Towards the end , a squadron of Danish ships met up with Dutch and escorted them into the harbor of Copenhagen . The Swedish fleet had failed ; much - needed reinforcements and supplies had reached the beleaguered Danish town . The combined Danish and Dutch fleet now had control of the seas , forcing the Swedish fleet to seek refuge in the harbor of Landskrona on the Swedish mainland . Attack on Copenhagen . After six months of siege the Dutch had re - opened the sea lanes . Charles now faced a difficult choice : if he tried to sue for peace , the conditions would have been worse than the previous peace . The other option was an all - out attack on Copenhagen , hoping that conquering the city would end the war . The number of Swedish attackers are somewhat uncertain , roughly 8 , 000 men , comprising 4 , 500 infantry , 2 , 000 cavalry , 1 , 000 sailors and a few hundred gunners . The king planned the attack meticulously , but neglected to uphold adequate secrecy ; the Danes were soon fully aware of the details of the Swedish attack plan thanks to a number of deserters and spies able to move between the encampments . The Danes had 6 , 000 trained soldiers , and an additional 5 , 000 men and women from the city had also taken up weapons , bringing the number of defenders to 11 , 000 . The Swedish forces had performed diversionary attacks on the outskirts of the city on two consecutive nights in order to tire the defenders , and at midnight on February 11 , 1659 , the main attack commenced . The main spearhead of the Swedish forces attacked from south of St . Jørgens lake with the King himself in overall command . A hundred cannons on Slotsholmen were brought to bear on the Swedish attackers with fast and accurate fire . The two attacking divisions advanced nevertheless , led by general - major Fabian von Fersen and general - major Johan von Essen . They reached the outer palisade s on the ice , which were quickly breached , but the Swedes were immediately stopped by holes in the ice that the Danes had cut . The bridges they had brought were not long enough after the ice moats had been widened with the help of Dutch marines . Caught on the ice , the Swedes were in the open and subject to heavy fire . Longer bridges were eventually brought , and the attack continued towards the city walls . The battle was ferocious , with the attackers desperately trying to establish a bridgehead on the walls . But in the end , the defenders were successful and the Swedes were thrown back . The northern attack force moved south towards Østerport where the fortification Kastellet laid . The Swedes got very close to Nyboder and were in the process of crossing the moat , when they fell victim to a well - conducted ambush , and withdrew with heavy losses . Around 6 in the morning , Charles X of Sweden knew that all attacks had failed . He ordered a retreat to the outskirts of the city , back to the starting position . The victory was important for the Danes . Not only had their arch - enemy been defeated , out of the smoldering city came a stronger bourgeoisie with renewed confidence , more privileges and an improved position vis - a - vis the Danish crown . In many ways , it was a new Denmark which emerged from the assault of its capital on February 12 , 1659 . The Allies invade Funen . When the Swedish invaded Zealand in August 1658 , Holland was not the only foreign power that took notice . A union between Brandenburg , Poland and Austria had already started to put together a relief army in December 1657 , but preparations of the polyglot force took so long that the Treaty of Roskilde was signed before the army was ready to march . However , the preparations were not in vain — with the 1658 invasion the allies were in an excellent position to quickly put together a force and march towards Denmark . Thanks to the earlier preparations , a large force of 14 , 500 Brandenburgers under Frederick William , 10 , 600 Austrians led by the Italian Field Marshal Raimondo Montecuccoli and 4 , 500 Poles led by Stefan Czarniecki had crossed the Oder on September 14 , 1658 . Swedish possessions in Central Europe all along the Baltic cost were under attack , and the Austrians at least were enthusiastic in Pomerania sending an army of 17 , 000 to lay a siege on Stettin where they joined 13 , 000 Brandenburgers . and also moved towards Jutland . However , the anti - Swedish coalition suffered internal conflicts . The Polish opinion of Austria was in rapid decline , and their enthusiasm for the campaign was at best lukewarm . Nevertheless , the allies managed to take possession over Jutland and the Swedish commander Philip of Sulzbach was forced into a long series of retreats . On May 19 , 1659 , the Swedes abandoned their last positions at Fredriksodde and took up positions at Funen . Less than two weeks later , on May 31 , 1659 the first allied assault on Funen began with 9 , 000 soldiers . Against them stood 4 , 000 Swedes , considerably fewer , but consisting of battle - hardened veteran s . The first attack was duly repelled . On June 26 , a second attempt was made : the allies landed after heavy fire had pounded what was thought to be the Swedish positions . However , the Swedes had pulled back and returned unscathed with heavy fire of their own . The invaders were again thrown back . Before a third attempt could be made , a Swedish naval squadron under Owen Cox managed to sink a large number of the invading fleet at the naval battle of Ebeltoft , and took 1 , 000 prisoners . In the end the allies had not succeeded to invade Funen , and a decision was taken to instead go back and attack Swedish Pomerania . Meanwhile , other European powers had decided that it was not in their interest that any one power should dominate the Baltic Sea . After long negotiations , known as the first Concert of the Hague , England sent a large fleet of 43 ships with more than 2 , 000 cannons . The force did not directly participate in fighting but nevertheless sent a clear message to the Dutch fleet patrolling the Danish waters . England worked hard to broker a peace , aided by France which also declared its willingness to help the Swedes if the Danes refused to negotiate . Battle of Nyborg . On November 11 Hans Shack and his forces boarded Dutch transport ships to take them to the east side of Funen . After some false starts , due to weather and Swedish resistance , he managed to land near Kerteminde . General - Major Ernst Albrecht von Eberstein was in charge of the allied forces that had been left on Jutland , and was also moving towards Funen ; landfall was made two days later without any Swedish resistance . Both Eberstein and Schack marched towards Odense , meeting up on November 12 . So far , the invasion of Funen was going smoothly for the combined Danish and allied forces . The Swedish commander Sulzbach made a tactical error in not attacking either Schack or Eberstein before they could join up , even though his generals urged him to do so . Instead , he chose to withdraw to Nyborg . The Swedish king was not pleased and immediately sent Gustaf Otto Stenbock to relieve Sulzback of his command . When Stenbock arrived he found the city ' s defenses wanting and sent a note to the king that he could not guarantee that he would hold the city . Instead of immediately taking advantage of the situation , Eberstein and Shack quarreled over who should command the combined forces . The impasse was finally resolved by Ebestein and Shack by agreeing that they would hold command the forces every other day . The Swedish commanders had decided they must try to make a stand . A few kilometers west of Nyborg the Swedish forces of about 5 , 500 men stood in battle formation in the way of the advancing forces . The Swedes had a good position , with a small lake on the left flank and a forest on the right , providing good cover for a retreat to Nyborg should it be necessary . Opposing them were 9 , 000 men , with Eberstein in command that day . They divided into two lines , each commanded by the respective commanders . Thrice Eberstein attacked ; only to be rebuffed by intensive Swedish fire and cavalry attacks . Eberstein himself was almost captured , only narrowly escaping . Even then , Eberstein refused to ask Schack for assistance in the battle . Colonel Ditlev Ahlefeldt of the allied forces would not to let pride and vanity be the downfall of the attack and pleaded with Schack to attack . Shack brandished his rapier and mounted a forceful attack into the Swedish left flank . A bloody engagement ensued , but the Swedish cavalry was no match for the rested Danish forces — they fled towards Nyborg leaving the infantry defenseless . The Polish riders showed no pardon , cutting down the Swedish infantry almost to a man . The Dutch also intervened with an expeditionary fleet led by Michiel Adriaenszoon de Ruyter . The Swedes had fought bravely . Salzback had personally dispatched 8 men . But their losses were heavy , over 2 , 000 men had been killed , almost half the force while the allies had lost 1 , 900 men . The defenses at Nyborg was in no condition to withstand a siege . There was nothing for the Swedish to do but to surrender , forcing 5 , 000 men into captivity ; Sweden had suffered a devastating defeat . The Latvian city of Mitau ( Jelgava ) fell to Polish - Lithuanian forces commanded by Aleksander Hilary Połubiński in January 1660 and the allies were preparing an invasion of Zeeland ; the outlook was not good for the Swedes . Fortunately for them , the war would soon end . Insurgencies . The Swedes were not popular in the regions that Sweden had gained at the Treaty of Roskilde in 1658 . With the new war going badly , insurgents saw their chance to rise up against the unpopular rule . Swedish response , especially in Scania , was more subtle than one might believe . An all out terror campaign would have been economically disastrous . Instead small patrols searching the woods were often employed combined with promises of carrots or sticks to the local farmers . Bohuslän and Frederikshald . The fortress of Fredriksten above the town of Frederikshald in Norway was attacked by Swedish forces and repulsed by the Norwegian army three times during the years 1658 - 60 . After each withdrawal the Swedes would return in greater force , but never succeeded in capturing the strong fortress . Norwegians called the battles in this theatre of war " bjelkefeiden " ( " the Bjelke feud " ) after the commander - in - chief of the Norwegian army , lieutenant general Jørgen Bjelke . After each attack on Frederiksten , Bjelke invaded the former Norwegian province of Bohuslän and twice succeeded in reconquering most of it . The first Swedish attack on Frederikshald started on 14 September 1658 with a force of 1600 under Harald Stake , who falsely believed the town to be undefended . But Frederikshald was defended by two companies of the civic militia under captain Peder Olsen Normand , who had taken up a position on the Overberget hill south of the town . Detachments from the regiments of Oppland and Østfold with four cannons came to their rescue . The Swedish attackers were taken by surprise and were completely defeated the day after their arrival . The second battle of Frederikshald took place in February 1659 . Harald Stake was back with 4000 men , who approached the town across the frozen inlet of Svinesund and opened artillery fire from the island Sauøya . He then let his infantry attack from the west across the river Tista . Its bridge was defended by some companies under Tønne Huitfeldt and Peder Normand . The Oppland and Østfold regiments together with four cavalry squadrons remained inside the town as strategic reserves . Bjelke , having arrived some days earlier , was in command of the Norwegian forces . The Swedes initially drove the defenders back across the Tista bridge , but were halted at the bridgehead . After heavy losses the Swedes retreated to the far side of the river . The Norwegians then prepared for a renewed attack by fortifying the weak spots around Frederikshald . An even greater Swedish force of 5000 soldiers ( of which 3000 were cavalry ) under Lars Kagg , Gustaf Horn and Harald Stake laid siege to Frederikshald in January 1660 . They captured some forward defensive positions , but the sudden death of Charles X on February 13 was a probable cause for lifting the siege February 22 . Trondheim . The Trøndelag province in which Trondheim is the largest city is situated in the center of Norway . As a result of the Treaty of Roskilde in 1658 , the cession of Trøndelag had divided Norway into two parts with no land connection between the north and south . Later that year , however , Trøndelag was reconquered by Norwegian army units under their commander - in - chief , lieutenant general Jørgen Bjelke . Already on September 28 , 1658 , a small fleet of three ships and several smaller boats landed the Norwegian forces close to Trondheim . The Swedish governor Claes Stiernsköld had 120 cavalry and 600 infantrymen under his command with the Swedish ship " Gotland " in the harbor of Trondheim . Two Dano - Norwegian ships attacked " Gotland " , thought no significant damage was inflicted on either side . A small Swedish reinforcement force arrived in Trondheim , but both food and ammunition were in short supply . On October 4 , the Norwegian forces arrived at the city reinforced by 1 , 000 peasants from the surrounding countryside who had taken up arms . When hearing that aid was near , the population of the city revolted , but the uprising within Trondheim was quickly suppressed . Charles X ordered Lieutenant Colonel Erik Drakenberg to assemble a force in Jämtland and march towards Trondheim , but the relief was stopped by Norwegian peasants that had taken to the hills and defended the mountain passages . The Norwegiann forces increased the pressure on Trondheim and red - hot shot rained down on the city daily . Despite Stiernsköld ' s swearing to " boil soup on his leather pants before surrendering " he was nevertheless forced to leave the city on December 11 . According to the terms of the surrender , Stiernsköld and his men were allowed to leave under military honors with 2 , 500 men presenting arms . Bornholm . On April 29 , 1658 Bornholm was presented with its new governor : Colonel Printzensköld , who arrived with his family and 130 soldiers . Printzensköld soon enacted a number of unpopular taxes and many of the island ' s young men were conscripted . In addition , had hit the island hard , killing half the population of 10 , 000 . The island was seething with anger and resentment , and after the Swedish invasion of Denmark Frederick III sent letters to leading men in the community , urging them to revolt . They wasted no time , and Printzensköld was shot dead during an inspection tour on December 8 , 1659 . The remaining Swedes , mostly Scanians who had little reason to be loyal to the Swedish King , surrendered . The Swedish navy was otherwise occupied and could offer no relief . Bornholm was again under Danish control . Scania . One of Frederick III ' s bodyguards , Statius , traveled to Scania to organize the peasants into Snapphane units and instigate anti - Swedish sentiment . In Malmö , a cabal of rich bourgeoisie , led by Bartholomaeus Mikkelsen , planned a revolt . The conspiracy tried to recruit one of Malmös two mayors , Efvert Wiltfang , but he would not commit himself to the uprising , even though he said he would support Frederick III . At the end of December , the Danes embarked on a foray into Scania , but were foiled by bad weather and poor navigation . Meanwhile , the Swedish authorities had become aware of the plot and the main leaders were arrested , among them Mikkelsen and Wildfang , and the conspirators were sentenced to death . On December 22 , 1659 Mikkelsen and two others were beheaded , but in an attempt to placate the Scanian people the execution of Wiltfang and 10 others was stayed . The uprising had been averted , but rebels and insurgents continued to operate in the countryside . Peace and aftermath . Charles X fell ill in the beginning of 1660 and died of pneumonia on the night of February 13 , 1660 . With the death of the Swedish king , one of the major obstacles to peace was out of the way ; in April the Treaty of Oliva was signed with the Allies ( Poland , Austria and Brandenburg ) . However , the Danes were not keen on peace after their recent success . After further concessions , the Dutch released the blockade on Landskrona , allowing the Swedish fleet out in the Øresund strait and blockade Copenhagen . Danish diplomacy soon got the Dutch back on their side again , and real war between Sweden and Holland seemed imminent . The French and English intervened in favor of the Swedes and the situation was again teetering on the edge of a major conflict . The Danish statesman Hannibal Sehested was instructed by Frederick III to negotiate with the Swedes , and the resulting peace treaty can largely be credited to him . Without any direct involvement by foreign powers , the Danes and Swedes managed to negotiate the Treaty of Copenhagen within weeks , much to the surprise of both parties . A bone of contention was the islands of Hven and Bornholm , the latter having received the Danish king ' s personal promise of protection . In the end , Bornholm remained under Danish control in exchange for a number of estates in the south of present - day Sweden . In the Treaty of Roskilde two years earlier , Denmark - Norway had been forced to cede the Danish provinces of Scania , Halland , Blekinge , the island of Bornholm and the Norwegian provinces Trøndelag and Båhuslen . The Treaty of Copenhagen reaffirmed the Swedish rule over Scania , Halland , Blekinge , and Bohuslän , while Bornholm and Trøndelag were returned . It was a significant victory for Denmark - Norway , but it did not result in a reversal of the costly earlier peace . The treaty of 1660 established political borders between Denmark , Sweden and Norway which have lasted to the present . The bold March across the Belts had threatened Copenhagen so seriously that it had won the previous war for Charles . When his attempt to follow through with his previous venture failed , he proved unable to suppress militarily the combined forces of his foes . Sweden had come close to dominating the Baltic , which was not in the interest of the major powers . England , France and to a lesser extent the Netherlands all favored a return to the status quo of the Roskilde peace . In Denmark , the war resulted in sweeping social changes . Frederick III browbeat the nobility which had long held power in Denmark into accepting a hereditary and absolute monarchy .