Swedish military history encompasses the military engagements and strategic developments of Sweden from prehistoric times to the present day. As a significant European power during the 17th and early 18th centuries, Sweden played a major role in shaping the political landscape of Northern Europe. The country's military history is marked by periods of expansionism, particularly during the Swedish Empire era, followed by a long-standing policy of armed neutrality. Key phases include the Viking Age, the rise of the Swedish Empire, involvement in the Thirty Years' War, the Great Northern War, and more recent participation in United Nations peacekeeping operations. Sweden's military strategies have evolved from aggressive expansion to a focus on territorial defense and international cooperation, reflecting changes in its geopolitical position and global security landscape. Despite maintaining official neutrality through both World Wars, Sweden has continued to adapt its military capabilities and policies in response to regional and global security challenges, including its recent decision to join NATO in response to changing European security dynamics.

Prehistoric Sweden and the Viking Age

During prehistoric times, Sweden was divided into two kingdoms: Svea and Göta. There were many wars fought between these kingdoms and eventually the Svea won. The Icelandic sagas tell of many family feuds as well, one can assume that these were common in Sweden also, as the structure of society was similar.

During the Early Middle Ages, many Vikings took recruitment in the fleet and participated both in trade and in plundering raids. The system of Leidang was used to organize the armies in the different parts of the country. In an alliance with the Danes, the Swedish king Olof Skötkonung won the war against the Norwegians at the battle of Svolder.

Middle Ages The Russo-Swedish War (1495–97) was a result of an alliance between Ivan III of Russia and Hans of Denmark, who was waging war against the Sture family of Sweden in the hope of regaining the Swedish throne. Ivan III sent Princes Daniil Shchenya and Vasily Shuisky to lay siege to the Swedish castle of Vyborg. The siege lasted for three months and ended when a castellan set his supply of powder on fire, thus "scaring the Muscovites out of their wits", as the Swedish records say. The following year Russian generals Vasily Kosoy and Andrey Chelyadnin severely devastated Swedish Finland as far as Hämeenlinna (Tavastehus). Another detachment sailed along the shore, forcing the Finns into subservience.

Sten Sture the Elder, who was then at Turku (Åbo), was enraged at the news of the Russian expedition and sent Svante Nilsson with 2,000 men to take Ivangorod, a new fortress which Ivan III had built to protect Russian Ingria against Livonian Knights. The fortress was taken but was impossible to defend it for a considerable period of time — Svante Nilsson proposed to hand it over to the Knights, an offer which they declined. Thereupon the Swedes set the fortress ablaze and sailed home. After the Swedish throne fell to Hans of Denmark, hostilities were suspended until 1508, when Sweden and Russia ratified a peace treaty for 60 years. Sweden and Russia would fight many wars in the following centuries (see Russo-Swedish Wars)

The Early Vasa era

Swedish War of Liberation

The Swedish War of Liberation (1521–1523) was a civil war in which the Swedish nobleman Gustav Vasa successfully deposed king Kristian II, as regent of the Kalmar Union in Sweden.

The De la Gardie Campaign

The De la Gardie Campaign refers to the actions of a 15,000-strong military unit commanded by Jacob De la Gardie in alliance with the Russian commander Mikhail Skopin-Shuisky against the Polish–Lithuanian Commonwealth in the Polish–Muscovite War (1605–18). The campaign was a result of an alliance between Charles IX of Sweden and Vasili IV of Russia, whereby the latter promised to cede the County of Kexholm to Sweden vs Estonia 1655.

The combined Russo-Swedish forces set out from Novgorod late in 1609 and marched towards Moscow, relieving the Siege of Troitse-Sergiyeva Lavra on their way. They dispersed the supporters of False Dmitry II, who maintained an alternative court in Tushino near Moscow and challenged the authority of Vasily IV. In the aftermath, some of the Tushino boyars summoned Wladyslaw IV to lay his claim to the Russian throne, while Skopin-Shuisky was poisoned at the behest of his uncle and rival, Prince Dmitry Shuisky.

In June 1610, De la Gardie and Dmitry Shuisky departed from Moscow in order to lift Żółkiewski's Siege of Smolensk. The campaign ended with most of De la Gardie's forces being destroyed by the Polish hetman Stanisław Żółkiewski at the Battle of Klushino in 1610. The De la Gardie Campaign can be considered a prelude to the Ingrian War.

The Ingrian War

The Ingrian War between Sweden and Russia, which lasted between 1610 and 1617 and can be seen as part of the Time of Troubles, is mainly remembered for the attempt to put a Swedish duke on the Russian throne. It ended with a large Swedish territorial gain in the Treaty of Stolbovo which laid an important foundation to Sweden's Age of Greatness.

The Kalmar War

The Kalmar War was a war between Sweden and Denmark 1611 to 1613. Sweden sought an alternative trade route to avoid paying Denmark's Sound Toll through Northern Norway. This was not to Denmark's liking and they invaded southern Sweden. England and the Netherlands were also invested in the Baltic Sea trade, and pressured to curtail Denmark's power by ending the Kalmar War before a decisive victory could be attained. The Danes, while well-equipped and strong, had relied heavily on mercenary forces and Christian IV, low on funds, was finally amenable to persuasion in 1613. With England's intercession, the Treaty of Knäred was signed on 20 January 1613.

Denmark reached its victory, restoring Norwegian control of Sweden's land route through Lapland by incorporating Sámi Lapland into Norway (and thus under Danish rule). Further, Sweden had to pay a high ransom for two fortresses captured by Denmark. Sweden, however, achieved a major concession — the right of free trade through the Sound Strait, becoming exempt of the Sound toll (a right shared by England and Holland).

Polish–Swedish Wars

The Polish–Swedish wars were a series of wars between the Polish–Lithuanian Commonwealth and Sweden, in the wider meaning to the series of wars in which both Sweden and the Polish–Lithuanian Commonwealth participated between 1563 and 1721, in the narrower meaning denoting the two wars between 1600 and 1629.

The Swedish Empire era

The Thirty Years' War

The Thirty Years' War was fought between 1618 and 1648, principally on the territory of today's Germany, and involved most of the major European continental powers, including Sweden. Although it was from the outset a religious conflict between Protestants and Catholics, the rivalry between the Habsburg dynasty and other powers was also a central motive.

Sweden held, for a time, control of the principal trade routes of the Baltic; and the increment of revenue resulting from this commanding position was of material assistance during the earlier stages of the war in Germany, whither the Swedish king Gustavus II Adolphus transferred his forces in June 1630. Gustavus, later to be called "the Lion of the North" due to his skills as a commander, intervened on the Protestant side in the German civil war. Using new military techniques such as lighter and more mobile artillery, a larger proportion of his infantry using firearms (as opposed to pikes), and cavalry shock tactics, he won a crushing victory at the Battle of Breitenfeld in 1631. In the Battle of Lützen on 6 November 1632 he rode into a group of enemy cavalry and was killed. The battle itself was a draw. Two years later Imperial troops won a convincing victory over the Protestant Army at Nördlingen. In order to prevent the Habsburg's from winning the war, France, who had already given major financial subsidies to Sweden, intervened on the Protestant side. The war dragged on for many years until a peace agreement was at last reached in 1648. In the Peace of Westphalia Sweden received an indemnity, as well as control of Western Pomerania and the bishoprics of Bremen and Verden. It thus won control of the mouth of the Oder, Elbe, and Weser Rivers, and acquired three voices in the Council of Princes of the German Reichstag.

The Torstenson War

The Torstenson war was a short period of conflict between Sweden and Denmark/Norway which occurred in 1643 to 1645 during the waning days of the Thirty Years' War. It was named after Lennart Torstenson.

Dutch-Swedish War

The Dano-Swedish War (1658–1660), was a Dutch intervention in the Northern Wars, in which Sweden tried to extend its control over the Baltic Sea.

Charles X's wars

Sweden attacked Poland in 1655. The goal was to gain full control over the Baltic Sea. During the two first years, Swedish troops occupied large parts of Poland and the war was almost won. In 1656, Sweden won the battle of Warsaw, but the Polish resistance hardened and the farmers began fighting a guerrilla war against the Swedes.

The war did not go well, and in the autumn of 1657, Denmark-Norway declared war against Sweden. Charles X took then the army and marched north. In October, the Swedes conquered Frederiksodde and on 30 January the Swedish army crossed the Little Belt; on 5–6 February they crossed the Great Belt, one of the biggest feats of the Swedish army. Denmark-Norway surrendered and handed over the Danish provinces of Blekinge, Bornholm, Halland and Scania as well as the Norwegian provinces of Trondheim and Båhuslen after the Treaty of Roskilde.

Wanting to follow up his victory, Charles X attacked Copenhagen in 1659, but was forced to withdraw because of the strong Danish defence and support from the Dutch navy. Norwegian forces succeeded in reconquering the province of Trondheim. The 1660 Treaty of Copenhagen restored Trondheim to Norway and Bornholm to Denmark.

The Scanian War

The Scanian War was fought between the union of Denmark–Norway and Sweden from 1675–1679. The war was prompted by the Swedish involvement in the Franco-Dutch War. Sweden had allied with France against several European countries. The United Provinces, under attack by France, sought support from Denmark-Norway.

The Danish objective was to retrieve the Scanian lands that had been given to Sweden after the Northern Wars. Although the Danish offensive was initially a great success, Swedish counter-offensives nullified much of the gain. The most important battle was fought at Battle of Lund were Swedish forces won a costly victory, this was a turningpoint in the war for Sweden. Eventually, a French-dictated peace was negotiated stipulating that all territory lost by Sweden be returned.

Great Northern War

The Great Northern War took place between 1700 and 1721. It was fought between a coalition of Russia, Denmark–Norway, and Saxony (also the Polish–Lithuanian Commonwealth, from 1701, and Prussia and Hanover from 1715) and Sweden, which was helped by the Ottoman Empire and monetary subsidized by France.

The war began as a coordinated attack on Sweden, ruled by the young Charles XII, by the coalition in 1700 and ended in 1721 with the Treaty of Nystad and the Stockholm treaties. Despite spectacular early Swedish victories, the ultimate result of the war was the end of the Swedish Empire. Russia supplanted Sweden as the dominant Power on the Baltic Sea and became a major player in European politics.

The Age of Liberty Hats and Caps