Finnish War
The Finnish War was fought between the Kingdom of Sweden and the Russian Empire from 21 February 1808 to 17 September 1809 as part of the Napoleonic Wars. As a result of the war, the eastern third of Sweden was established as the autonomous Grand Duchy of Finland within the Russian Empire. Other notable effects were the Swedish parliament's adoption of a new constitution and the establishment of the House of Bernadotte, the new Swedish royal house, in 1818.
Background
After the Russian Emperor Alexander I concluded the 1807 Treaty of Tilsit with Napoleon, Alexander, in his letter on 24 September 1807 to the Swedish King Gustav IV Adolf, informed the king that the peaceful relations between Russia and Sweden depended on Swedish agreement to abide by the limitations of the Treaty of Tilsit which in practice meant that Sweden would have been required to cut off trade with Britain in accordance with the Continental System. The king, who viewed Napoleon as the Antichrist and Britain as his ally against Napoleon's France, was apprehensive of the system's ruinous consequences for Sweden's maritime commerce. He instead entered into negotiations with Britain in order to prepare a joint attack against Denmark, whose Norwegian possessions he coveted.In the meantime, the Royal Navy attacked Copenhagen and the Anglo-Russian War was declared. Referring to the treaties of 1780 and 1800, the emperor demanded that Gustav Adolf close the Baltic Sea to all foreign warships. Although he reiterated his demand on November 16, 1807, it took two months before the king responded that it was impossible to honor the previous arrangements as long as the French were in control of the major Baltic ports. King Gustav Adolf did this after securing an alliance with Britain on 8 February 1808. Meanwhile, on 30 December 1807 Russia announced it would be forced to act should Sweden not give a clear reply.
Although most Swedish officers were sceptical about their chances in fighting the larger and more experienced Imperial Russian Army, Gustav Adolf had an unrealistic view of Sweden's ability to defend itself against Russia. In Saint Petersburg, his stubbornness was viewed as a convenient pretext for Russia to occupy Finland, thus pushing the Russo-Swedish frontier considerably to the west of the Russian capital and safeguarding it in case of any future hostilities between the two powers.
The situation was problematic for Sweden, since it once again faced both Denmark and Russia as potential enemies requiring the Swedes to split their forces. The king had thought it impossible to defend Finland should the enemy attack during the winter and chose largely to ignore the repeated warnings of the Russian threat he received in early 1808. Most of the Swedish plans assumed that warfare would be impossible during winter, disregarding the lessons from recent wars. In addition, several new good roads had been built into Finland greatly reducing the earlier dependency on naval support for any large operation in Finland.
The Swedish plan was to first passively defend and hold on to the fortifications in the southern coast of Finland, in which Sweden had strong garrisons, while the rest of the Swedish Army retreated to the north. Then in the spring, counterattack simultaneously from north and south, when the Swedish army would have naval support and the Russian army would be spread over Finland and thus have long supply lines. The basic reason for the plan was to avoid major decisive battles.
Some advocates existed for taking a more active approach immediately, namely Lieutenant Colonel Samuel Möller who advocated for taking an immediate offensive and Gustaf Mauritz Armfelt who supported actively delaying the advancing enemies in co-operation with the garrisons on the southern coast.
In the end, instructions which the new Swedish commander in Finland, General Wilhelm Mauritz Klingspor, received from the king were an unsuccessful and open-ended mixture of ideas from these very different plans.
Russia had gathered a wealth of information from Finland using spies and other sources. The level of detail was so great that Russian maps of Finland were in many respects more accurate than their Swedish counterparts. The Russians used the services of General Georg Magnus Sprengtporten when forming their plans. Sprengtporten suggested going on to an offensive during the winter since Finland would be mostly isolated when seas were frozen. His ideas were further developed by General Jan Pieter van Suchtelen before General Friedrich Wilhelm von Buxhoeveden was appointed as the commander of the Russian army in Finland in December 1807.
The plan involved using the series of fortifications built after 1790 as staging grounds for the Russian advances into Finland. In southern Finland, armies were to isolate the fortifications and first take control of the whole of southern Finland before advancing further to the north. Forces in Savonia were to press hard against the Swedes and reach the Gulf of Bothnia towards Oulu and Vaasa to cut off the retreat of the main body of the Swedish army.
February–May 1808
On February 21, 1808, 24,000 Russian troops under Friedrich Wilhelm von Buxhoevden crossed the Swedish–Russian border in Ahvenkoski and took the town of Loviisa. Since Klingspor had not arrived, Lieutenant General Karl Nathanael af Klercker acted as Swedish commander in Finland. He was notified of the Russian invasion already on 21 February and since it was impossible to hold the predefined defense lines as the army had not yet fully assembled, he ordered the army to assemble at Hämeenlinna. Before the engagement started, Klingspor finally arrived on 2 March and assumed command. Instead of facing the Russians at Hämeenlinna, he ordered the army to withdraw. In Savonia the Russians also forced the Swedes to withdraw. The king was quite unprepared for the attack, especially as war was not declared until April. About 21,000 Swedish troops were stationed in various fortresses in Finland, while the rest of his army was unable to leave southern Sweden for fear of Danish attack.File:Kuopio 1808.jpg|thumb|right|The Swedish assault on the chancellery in Kuopio during the Battle of Kuopio
The Russian advance was swift. On the first day of the war they had captured the town of Loviisa and besieged the Swedish sea fortress of Svartholm. Porvoo was captured on 24 February and Helsinki on 2 March. Abandoned Swedish fortifications on the Hanko Peninsula were taken and manned on 21 March and on the same day the Russian army took Turku while a small detachment was sent to Åland. Before the end of March 1808 even Vaasa was taken. In Savonia, Russians also advanced rapidly and took Kuopio on 16 March. Swedish forces had mostly just withdrawn before the advancing Russian often destroying usable materials. For example, the Swedish archipelago fleet's ships that had been docked in Turku were torched to prevent their capture.
The Swedish fortress of Svartholm, commanded by Major Carl Magnus Gripenberg, was ill-prepared for a war. While the garrison was 700 men strong, only a third of the men had actually functioning weapons, while most of the fortress' guns had no carriages. The fortress had fallen into disrepair and lacked both adequate food and ammunition stores. Even the wells were found to be unusable. After starting the siege on 21 February, the Russians issued a surrender demand for the fort, but this was refused by the Swedes. The demand was repeated on 2 March but without success. After a meager Russian bombardment, Gripenberg agreed to negotiations on 10 March. The fortress surrendered to the Russians on 18 March after a siege that had lasted roughly a month, with just one man having been wounded in action.
Sveaborg under Admiral Carl Olof Cronstedt had been well prepared for the war with a garrison of 6,000 men, over 700 cannons, and enough stores to last until the summer of 1808. Defenses were strong enough to prevent the Russians from trying to storm the fortress by surprise. Instead the Russians laid siege to Sveaborg. The fortress surrendered on 6 May 1808 after prolonged negotiations with the Russians as the commanding officer Carl Olof Cronstedt and his council believed that resistance was futile. The Russians gained the main body of the Swedish archipelago fleet intact as well as large stores of supplies and munitions.
The Russians had advanced considerably but they had also gained the long and vulnerable coastline with it. After the sea would be clear of ice there would be nothing to prevent Swedish forces from landing troops on the shore. With the Royal Navy supporting the Swedish Navy there was little the Russian Baltic Fleet could accomplish. Capture of the main body of the Swedish archipelago fleet had resulted in a real advantage to the Russians since it allowed them to gain superiority in the narrow waters of the Finnish archipelago where large ships of the line could not operate. Even the powerful explosion at Sveaborg which destroyed several of the captured ships did little to change Russian superiority in the Finnish archipelago. The Russians utilized the guns from the burned ships, and from those which burned during the winter, and constructed several fortifications on the coast, both in Hanko as well as along narrow passages leading to Turku.
Under Colonel Carl Johan Adlercreutz the Swedish army counter-attacked at Siikajoki and began to halt the Russian offensive. Soon after at the Battle of Revolax, the Swedish army under Colonel Johan Adam Cronstedt started an advance towards the south. These successes yielded a promotion to Field Marshal for Wilhelm Mauritz Klingspor. The Swedish advance was very slow however, as operations were often halted due to the thaw. An exception was the brigade under Colonel Johan August Sandels, which swiftly advanced towards Kuopio. Nikolay Tuchkov, a Russian general who was dispatched to the north of Finland, left garrisons in every fort along his way. This reduced his unit to 4,000 troops, which proved insufficient to pacify the hostile country. The Finns rose up in guerrilla fighting as far east as Frederikshamn within the Old Finland province of Russia.
In May, the Russians suffered further setbacks when they were driven from Gotland and Åland, where a Swedish flotilla, supported by the local population, compelled the small Russian force left on the main island of Fasta Åland to surrender, and then invaded the island of Kumlinge where the bulk of the Russian garrison on the Åland Islands was based. After a two-hour-long battle, the local militia, together with the Swedish landing force, overwhelmed their enemies and Colonel Vuich and his garrison were compelled to surrender.
On May 26, a British fleet carrying 14,000 troops under Sir John Moore entered the port of Gothenburg. Due to various disagreements with the Swedish king, however, they never landed and sailed off to fight the French in Spain after leaving 16 battleships and 20 other ships at Sweden's disposal.