Hovedøya is one of several small islands off the coast of

Oslo Oslo ( , , or ; sma, Oslove) is the capital and most populous city of Norway. It constitutes both a county and a municipality. The municipality of Oslo had a population of in 2022, while the city's greater urban area had a population ...

Norway Norway, officially the Kingdom of Norway, is a Nordic country in Northern Europe, the mainland territory of which comprises the western and northernmost portion of the Scandinavian Peninsula. The remote Arctic island of Jan Mayen and the ...

in the

Oslofjord The Oslofjord (, ; en, Oslo Fjord) is an inlet in the south-east of Norway, stretching from an imaginary line between the and lighthouses and down to in the south to Oslo in the north. It is part of the Skagerrak strait, connecting the Nor ...

. The island is quite small, no more than 800 metres across in any direction, the total area is 0,4 square kilometre. It is well known for its lush and green nature, with a wide variety of trees, bushes and flowers. For many, many years there was a military base on the island.

The name

The name is from Norse times (''Hǫfudøy''). The first element is ''hǫfud'' 'head' (here in the sense 'hill' or 'height'), the last element is the finite form of ''øy'' 'island'. The name is a reference to the top of the hill on the island - at 47 metres it is the tallest point of the inner Oslofjord islands by a good margin. (See also Nakholmen.)

History

The Cistercian

monastery A monastery is a building or complex of buildings comprising the domestic quarters and workplaces of monastics, monks or nuns, whether living in communities or alone ( hermits). A monastery generally includes a place reserved for prayer whi ...

, Hovedøya Abbey, was built on the island, and opened on 18 May 1147. During the

Medieval period In the history of Europe, the Middle Ages or medieval period lasted approximately from the late 5th to the late 15th centuries, similar to the post-classical period of global history. It began with the fall of the Western Roman Empire a ...

, the monastery was a leading economical force in the Oslo region. It was, however, closed down before the

Reformation The Reformation (alternatively named the Protestant Reformation or the European Reformation) was a major movement within Western Christianity in 16th-century Europe that posed a religious and political challenge to the Catholic Church and in ...

after the abbot came into conflict with King Christian II. The military official at

Akershus Fortress Akershus Fortress ( no, Akershus Festning, ) or Akershus Castle ( no, Akershus slott ) is a medieval castle in the Norwegian capital Oslo that was built to protect and provide a royal residence for the city. Since the Middle Ages the fortress ...

had the abbot imprisoned and the monastery looted and burned down in 1532. Parts of the ruins of the monastery remain on the island, but much of the stonework was used in the expansion of Akershus Fortress in the 17th century. The island has also been used for military installations, and former military buildings and artillery remain on the island. When Denmark-Norway became involved in the

Napoleonic war The Napoleonic Wars (1803–1815) were a series of major global conflicts pitting the French Empire and its allies, led by Napoleon I, against a fluctuating array of European states formed into various coalitions. It produced a period of Fren ...

, two cannon batteries were built to defend

and

in 1808 (again using the monastery ruins as a quarry). Four depots for gunpowder were built in 1826 on the high points of the island to ward off intruders, and a fifth was built in 1867. On the eastern half of the island is a Victorian house, popularly known as the "Laboratory". It was used by Director of Armory Ole Herman Johannes Krag, co-inventor of the

Krag–Jørgensen The Krag–Jørgensen is a repeating bolt-action rifle designed by the Norwegians Ole Herman Johannes Krag and Erik Jørgensen in the late 19th century. It was adopted as a standard arm by Norway, Denmark, and the United States. About 300 we ...

rifle in the late 19th century. There was once a large German camp on the island, with several barracks, which would later be turned into National Internment Camp for Women in Hovedøya. Today, only a single barracks from the camp remains, located near the ruins of the monastery. Today the island is a destination for tourists and bathers, who can enjoy the island's natural environment, pastures, historic buildings as well as fairly benign (for Norway) bathing temperatures.

Natural history

The island has an interesting

geology Geology () is a branch of natural science concerned with Earth and other astronomical objects, the features or rocks of which it is composed, and the processes by which they change over time. Modern geology significantly overlaps all other Ea ...

, being composed mainly of

Ordovician The Ordovician ( ) is a geologic period and system, the second of six periods of the Paleozoic Era. The Ordovician spans 41.6 million years from the end of the Cambrian Period million years ago (Mya) to the start of the Silurian Period Mya. T ...

and some Silurian mudstone and

limestone Limestone ( calcium carbonate ) is a type of carbonate sedimentary rock which is the main source of the material lime. It is composed mostly of the minerals calcite and aragonite, which are different crystal forms of . Limestone forms whe ...

. The transition between rocks of the two periods is exposed on the south-eastern tip of the island, illustrating the sudden marine transgression that marks the shift between two important parts of Earths history. The sequence has been affected by both

folding Fold, folding or foldable may refer to: Arts, entertainment, and media * ''Fold'' (album), the debut release by Australian rock band Epicure * Fold (poker), in the game of poker, to discard one's hand and forfeit interest in the current pot *Abov ...

and thrusting as part of the

Caledonian orogeny The Caledonian orogeny was a mountain-building era recorded in the northern parts of the British Isles, the Scandinavian Mountains, Svalbard, eastern Greenland and parts of north-central Europe. The Caledonian orogeny encompasses events that ...

with the strata lying vertically or in some case becoming overturned. The island is cross-cut by diabase dikes associated with a major rift in the Oslo area in the

Permian The Permian ( ) is a geologic period and System (stratigraphy), stratigraphic system which spans 47 million years from the end of the Carboniferous Period million years ago (Mya), to the beginning of the Triassic Period 251.9 Mya. It is the last ...

. The diabase has been heavily quarried for building material, and the island has about 20 quarries dating from the medieval period through to the 19th century. The oldest rock on the island dates back to late Ordovician and the eastern parts is littered with erratic boulders deposited during the last ice Age, thus the island illustrates well the local geological events spanning nearly half a billion years. The mostly sedimentary geology has given the island a very fertile

soil Soil, also commonly referred to as earth or dirt Dirt is an unclean matter, especially when in contact with a person's clothes, skin, or possessions. In such cases, they are said to become dirty. Common types of dirt include: * Debri ...

, giving it Norway's highest

biodiversity Biodiversity or biological diversity is the variety and variability of life on Earth. Biodiversity is a measure of variation at the genetic (''genetic variability''), species (''species diversity''), and ecosystem (''ecosystem diversity'') l ...

found in such a small place. A few plant species found on the island do not occur anywhere else in Norway. Due to the geology and natural diversity, the island has been declared a natural preserve. While no part of the island is off limit to the public, collecting plants and taking rock-samples is banned.

Visiting Hovedøya

The island is connected to Oslo by means of two boat routes (lines B1 and B4) which dock on the north side of the island. Service is year-round although it's only running during daylight and therefore is limited during the winter season. In summer time a small cafeteria right by the monastery ruins is open to the general public.

Curiosities

There is a fox living on the island that is often photographed by internet users and is known to occasionally steal things.

References

External links

Katolsk.no
Catholic webpage about the monastery
OsloSurf.no
entry on Hovedøya
Hovedøya
www.visitoslo.com {{DEFAULTSORT:Hovedoya Islands of Oslo