Suomenlinna (FI)

History of the Suomenlinna Sea Fortress

Suomenlinna - Over 270 years off the coast of Helsinki

The history of Suomenlinna is closely linked to the history of Finland. Suomenlinna is one of the largest sea fortresses in the world and is located about one kilometre off the coast of Helsinki. Suomenlinna was originally a bastion fortress built on an archipelago. It consisted of four closed fortifications, each on its own island, supplemented by open fortifications on two other islands. Within its walls was a garrison town with barracks and residential buildings as well as a naval base with dry docks and storage facilities.

Until 1808, Suomenlinna was a fortress built by Sweden to defend the whole of Finland and was also a powerful naval base. Today, Suomenlinna is one of Finland's most important sights, a popular recreational area and a residential neighbourhood with around 850 inhabitants.

The foundation of Suomenlinna

At the beginning of the 18th century, the Kingdom of Sweden lost all of its eastern border provinces and fortresses in two wars. To prevent the loss of the whole of Finland, the Diet decided to build a central fortress to protect the eastern part of the kingdom. Construction began in 1748 under the direction of Augustin Ehrensvärd. A few years later, the fortress was given its original name Sveaborg, which, in linguistic usage, quickly became Viapori changed.

Over the course of forty years, soldiers from the allotment system built a fortress off the coast of Helsinki, the total length of which was around 8 kilometres. Viapori became the largest fortress in the Swedish Empire.

The Russian era in Suomenlinna

Suomenlinna was conquered during the Finnish War in 1808 after a siege lasting several weeks. It then remained a Russian fortress for 110 years. Large barracks and hospitals were built for the garrison, but the Russian Empire no longer considered it necessary to reinforce the fortress itself. For this reason, an Anglo-French fleet was able to bombard the fortress without resistance during the Crimean War in 1855, causing considerable damage. After the war, a new sea defence line with earthworks and 9- and 11-inch cannons was built. The Suomenlinna dockyard was also rebuilt after the damage caused by the bombardment.

Suomenlinna for the Finns

On 12 May 1918, the Finnish flag was ceremonially hoisted on Kustaanmiekka in the presence of Regent Svinhufvud and the Senate. The fortress was then given the name Suomenlinna and served as a Finnish garrison for more than fifty years. In 1973, the v s area was placed under civilian administration and managed by the v s Administrative Board. The Naval Academy still operates in Suomenlinna today.

The Ehrensvärd Society was founded in 1921 with the aim of raising awareness of Suomenlinna and its history and preserving this valuable cultural heritage. Suomenlinna is a UNESCO World Heritage Site and receives over a million visitors every year.

Fortress architecture

The 18th century: A fortress adapted to the landscape and the empire

Construction of Suomenlinna began in 1748 under Swedish rule, at a time when European fortification theory was heavily influenced by French bastion systems. However, the resulting fortress was far from a rigid geometric ideal. Instead, it adapted to the irregular shapes of the archipelago. The rocky topography determined the contours of the defence walls, and in some places steep rock faces were cut away vertically and integrated directly into the fortifications (steep embankments). The result was an asymmetrical composition adapted to the landscape rather than a symmetrical star-shaped citadel.

The leading figure in the project was the commander Augustin Ehrensvärd, who combined technical military expertise with artistic sensibility. Although Suomenlinna was first and foremost a defensive structure designed to repel attacks from the sea, it was also conceived as a representative complex. The King's Gate in Kustaanmiekka and the Great Court (Suuri linnanpiha) functioned as ceremonial and administrative centres that demonstrated the authority of the Swedish crown.

Unlike many bastion fortresses on the continent, Suomenlinna's walls were generally straight rather than angled, and their upper mouldings (cordon curves) were thickened and extended to protect the masonry from rainwater. Functionality was paramount, but aesthetics were not neglected either. Ehrensvärd drew on the principles of late Baroque, French Classicism and Rococo in his spatial compositions, particularly in the arrangement of the inner courtyards and representative façades.

The collaboration between Ehrensvärd and the Swedish court architect Carl Hårleman** characterised the early stylistic ambitions, although few of Hårleman's direct designs were implemented. Nevertheless, his drawings circulated as models and influenced local designers and officers. The planning was carried out in Suomenlinna but sent to Stockholm for royal approval, reflecting the centralised control over architecture as a political instrument.

Suomenlinna was more than a fortress: it was a functioning military town. Only about a tenth of the buildings were purely for defence. Most served both fortification and practical purposes - barracks, bakeries, breweries, hospitals, workshops and huge warehouses. The naval base required dry docks, ropeworks, sailmakers and warehouses. The complex, which was largely built by Finnish soldiers, craftsmen and some prisoners using locally quarried stone, epitomised both pragmatic engineering and imperial ambitions. At the beginning of the 19th century, it was home to thousands of inhabitants, including families of soldiers.

The 19th century: Russian rule and stylistic change

After Finland was annexed to the Russian Empire in 1809, Suomenlinna entered a new phase. Its strategic location contributed to Helsinki being chosen as the capital in 1812. The Russians regarded the fortress as largely modern and retained its defensive character by extending the artillery zones to the east and west onto the surrounding islands. Nevertheless, the architectural focus gradually shifted from grand fortification projects to maintenance and new functional buildings.

The planning was initially carried out centrally under imperial supervision in St. Petersburg. The designs were scrutinised by the engineering department of the Ministry of War. Architects favoured by the emperor, including Carl Ludwig Engel and Konstantin Ton, shaped the concept of the fortress. Engel's ambitious design from 1820 for a huge barracks complex with a church and officers' wings was never realised, but shows how Suomenlinna was intended as a monumental imperial statement.

In the mid-19th century, Empire-style architecture characterised new functional buildings such as barracks, kitchens and laboratories. In addition, imperial symbolism - in particular the double-headed eagle of the Romanovs - was prominently displayed above gates and gables. From the 1860s, there was a revival of different styles: neo-Gothic elements appeared in brick barracks and service buildings, while neo-Renaissance forms characterised the officers' clubs and residences.

Suomenlinna functioned as a densely populated garrison town with around 4,000 inhabitants, including soldiers, officers, families, merchants and prisoners. The social hierarchy was clearly visible in the spatial distribution: a small officer class occupied a disproportionately large share of the living space. Wooden houses were particularly prevalent in the merchant neighbourhoods on Iso Mustasaari, where decorative verandas and gabled facades reflected the influence of Russian folk architecture. Although stone buildings were considered ideal, wood was often used for practical reasons.

The 20th century: From fortress to national monument

In May 1918, after Finland gained independence, the fortress was renamed Suomenlinna. The fortress, which no longer had any strategic significance, was soon recognised as a historical monument. Early observers described it as neglected and dilapidated, but this decay strengthened the case for its preservation.

In 1919, the town planner Birger Brunila drew up a masterplan in which he envisaged Suomenlinna as a multifunctional area combining military, residential, industrial and cultural uses. Parts of the islands were declared museum areas and restoration work began in the 1920s and 1930s. Influenced by contemporary Nordic classicism, the restorations emphasised symmetry, clarity and „Swedishness”, sometimes removing additions from the Russian period.

After the Second World War, the fortress gradually passed from military control to civilian administration. The coastal artillery remained active until the 1970s, but cultural and residential use increased. The restoration philosophy also evolved: the massive concrete repairs of the mid-20th century gave way to conservation measures that respected historical layers and traditional materials.

The 1974 management plan defined three permanent goals: the preservation of Suomenlinna as a national and international monument, its development as a cultural and recreational area and its preservation as a vibrant residential neighbourhood. These principles still guide the measures today. In 1991, Suomenlinna was inscribed on the UNESCO World Heritage List, confirming its global significance, and on 12 May 1918, the Finnish flag was ceremoniously raised on Kustaanmiekka in the presence of Regent Svinhufvud and the Senate. The fortress was then given the name Suomenlinna and served as a Finnish garrison for more than fifty years. In 1973, the v s area was placed under civilian administration and managed by the v s Administrative Board. The Naval Academy still operates in Suomenlinna today.

The Ehrensvärd Society was founded in 1921 with the aim of raising awareness of Suomenlinna and its history and preserving this valuable cultural heritage. Suomenlinna is a UNESCO World Heritage Site and receives over a million visitors every year.