Hovedøya is one of several small islands off the coast of

Oslo Oslo ( or ; ) 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 of 1,064,235 in 2022 ...

Norway Norway, officially the Kingdom of Norway, is a Nordic countries, Nordic country located on the Scandinavian Peninsula in Northern Europe. The remote Arctic island of Jan Mayen and the archipelago of Svalbard also form part of the Kingdom of ...

in the

Oslofjord The Oslofjord (, ; ) is an inlet in southeastern Norway. The fjord begins at the small village of Bonn in Frogn, Frogn Municipality and stretching northwards to the city of Oslo, and then curving to the east and then south again. It then flows s ...

. The island is quite small, no more than 800 metres across in any direction, the total area is 0,4 square kilometre. Its population is 5. 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 The Cistercians (), officially the Order of Cistercians (, abbreviated as OCist or SOCist), are a Catholic religious order of monks and nuns that branched off from the Benedictines and follow the Rule of Saint Benedict, as well as the contri ...

monastery A monastery is a building or complex of buildings comprising the domestic quarters and workplaces of Monasticism, monastics, monks or nuns, whether living in Cenobitic monasticism, communities or alone (hermits). A monastery generally includes a ...

, 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 5th to the late 15th centuries, similarly to the post-classical period of World history (field), global history. It began with the fall of the West ...

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

Reformation The Reformation, also known as the Protestant Reformation or the European Reformation, was a time of major Theology, theological movement in Western Christianity in 16th-century Europe that posed a religious and political challenge to the p ...

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

Akershus Fortress Akershus Fortress (, ) or Akershus Castle ( ) 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 has been the namesake and centre of the ...

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 {{Infobox military conflict , conflict = Napoleonic Wars , partof = the French Revolutionary and Napoleonic Wars , image = Napoleonic Wars (revision).jpg , caption = Left to right, top to bottom:Battl ...

, 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 German(s) may refer to: * Germany, the country of the Germans and German things **Germania (Roman era) * Germans, citizens of Germany, people of German ancestry, or native speakers of the German language ** For citizenship in Germany, see also Ge ...

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 the Earth and other astronomical objects, the rocks of which they are composed, and the processes by which they change over time. Modern geology significantly overlaps all other Earth ...

, being composed mainly of

Ordovician The Ordovician ( ) is a geologic period and System (geology), system, the second of six periods of the Paleozoic Era (geology), Era, and the second of twelve periods of the Phanerozoic Eon (geology), Eon. The Ordovician spans 41.6 million years f ...

and some

Silurian The Silurian ( ) is a geologic period and system spanning 23.5 million years from the end of the Ordovician Period, at million years ago ( Mya), to the beginning of the Devonian Period, Mya. The Silurian is the third and shortest period of t ...

mudstone Mudstone, a type of mudrock, is a fine-grained sedimentary rock whose original constituents were clays or muds. Mudstone is distinguished from ''shale'' by its lack of fissility.Blatt, H., and R.J. Tracy, 1996, ''Petrology.'' New York, New York, ...

and

limestone Limestone is a type of carbonate rock, carbonate sedimentary rock which is the main source of the material Lime (material), lime. It is composed mostly of the minerals calcite and aragonite, which are different Polymorphism (materials science) ...

. 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 and

thrusting Thrust is a reaction force described quantitatively by Newton's third law. When a system expels or accelerates mass in one direction, the accelerated mass will cause a force of equal magnitude but opposite direction to be applied to that syst ...

as part of the

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

with the strata lying vertically or in some case becoming overturned. The island is cross-cut by

diabase Diabase (), also called dolerite () or microgabbro, is a mafic, holocrystalline, subvolcanic rock equivalent to volcanic basalt or plutonic gabbro. Diabase dikes and sills are typically shallow intrusive bodies and often exhibit fine-gra ...

dikes Dyke or dike may refer to: General uses * Dyke (slang), a slang word meaning "lesbian" * Dike (geology), formations of magma or sediment that cut through and across the layering of adjacent rocks * Dike (mythology), ''Dikē'', the Greek goddess ...

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 251.902 Mya. It is the s ...

. 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, is a mixture of organic matter, minerals, gases, water, and organisms that together support the life of plants and soil organisms. Some scientific definitions distinguish dirt from ''soil'' by re ...

, giving it Norway's highest

biodiversity Biodiversity is the variability of life, life on Earth. It can be measured on various levels. There is for example genetic variability, species diversity, ecosystem diversity and Phylogenetics, phylogenetic diversity. Diversity is not distribut ...

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