Following the Finnish War (1808–1809), Finland was incorporated into the Russian Empire During that war, the fortress of Viapori saw proper military action for the first time in its history. The war was a result of a peace treaty signed by Napoleon, who had declared himself Emperor of France, and Alexander III, Emperor of Russia, in Tilsit in 1807, according to which Alexander was to persuade Sweden and Denmark to join Napoleon’s Continental Blockade directed against Britain. The war resulted in the whole of Finland being incorporated into Russia.

The siege and surrender of Viapori

The Russians decided to attack in winter, as in winter Sweden and Britain would be unable to launch a counteroffensive. Launched in February 1808, the Russian attack made good progress, and in early March the Russians occupied Helsinki. The Viapori fortress was besieged by the Russians.

On 19 March, the Russians began to bombard the Viapori fortress. Psychological warfare was more active than ordinary military operations. The garrison was fed exaggerated information on the superior strength of the besiegers, the friendliness of the Russians was praised, and the Swedish leadership was persuaded to surrender.

On 22 March, the Russians occupied Turku, and on the same day, the commander of Viapori, C.O. Cronstedt, met Russian officers, who were led blindfolded to the fortress in order to negotiate. The Russians painted a picture of the situation, according to which defending Viapori would be futile as France and Denmark were about to occupy Skåne, the southernmost province in Sweden. On the following day, the Swedes and Russians negotiated in Lonna, an island off Viapori. Cronstedt with his closest men rejected the offer for surrendering that the Russian had presented.

On 28 March, the Russians began to bombard Viapori again, with the bombardment lasting for five days. The garrison’s faith in the meaningfulness of the battle had declined, and new attempts to negotiate did not lead to any consensus. Finally Cronstedt decided that Viapori’s gunpowder supplies were insufficient for the defense of the fortress. On 6 April, he agreed to accept the terms according to which Viapori would surrender unless five battleships of the line arrived to support the fortress by 3 May. Relief never materialised, and Viapori was surrendered to the Russians.

Although Cronstedt had made miscalculations and had allowed propaganda to weaken the morale of the defenders, he was right regarding Viapori’s chances to defend itself, and probably saved human life by taking the decision to surrender. However, Cronstedt’s contemporaries regarded him as a traitor who had surrendered “the Gibraltar of the north” without giving battle.

Viapori’s significance for the Russians

As early as in April 1808, Emperor Alexander announced to the foreign powers that as of that date, Finland would be a permanent part of Russia. After Viapori had surrendered, a spectacular victory parade was arranged in St. Petersburg. This highlighted the significance of the fortress; the invincible Gibraltar of the north was now in Russian possession. Emperor Alexander visited Viapori twice in 1809, an indication of the considerable esteem that the sea fortress enjoyed in its new mother country. Viapori had a clear function; it was tasked with repelling any landing operations from the south and acting as a naval base. Part of the Russian Baltic Fleet was also transferred to Viapori. It should be highlighted that Viapori was a Russian base, not part of the Grand Duchy of Finland. Viapori played an important role in the defence of St. Petersburg.

The first Diet during the Russian era was held in Porvoo in 1809. After the Estates had sworn their oaths of allegiance to the Emperor, Finland was given the status of an autonomous Grand Duchy, and the country was allowed to retain its constitution and the privileges of the Estates dating back to the Swedish era. In 1812, Helsinki was declared the capital of Finland, which can be attributed to the existence of Viapori.

Read more about the fortress during the Russian period