The Battle of Suomenlinna marked a significant moment during the Åland War, part of the larger Crimean War. Fought in 1855, this engagement was characterized by an assault on the Russian-built fortress of Suomenlinna, which stood strategically on an archipelago near Helsinki. The fortress was key to Russian naval operations in the Baltic Sea and provided a defense line against potential attacks from allied forces, which included Britain and France. As tensions escalated over territorial control and maritime security, allied naval forces amassed, ready to launch an offensive aimed at crippling Russian capabilities and fortifying their influence in the region.

The allied fleet comprised over 30 warships equipped with advanced artillery for that time and focused their efforts on delivering a sustained bombardment against the fortress. The Russians stationed at Suomenlinna were prepared for the attack, but the superior artillery capabilities of the allies ultimately forced the defenders to retreat. This battle exemplified the evolving nature of 19th-century warfare, highlighting the shift towards coastal naval engagements and the importance of artillery technology. The conflict continued for several days, with the allied forces employing naval tactics that would influence modern military doctrine.

The aftermath of the battle saw severe damage to the fortress and significant losses on both sides, which played a crucial role in the campaign's trajectory. As the siege continued, the allies pressed heavily upon the defenses of Suomenlinna, leading to dramatic shifts in control of the region's maritime routes. The successful assault on the fortress not only weakened Russia's stance in the Baltic but also set a precedent for future military engagements in coastal territories, emphasizing the role of combined naval and land forces.