Main photo by Wilhelm Joys Andersen (CC BY-SA 2.0)
A seven-minute ferry ride from Rådhusbrygge delivers you to an island that has been a monastery, a shipyard, a fortress, a bathing resort, a German military camp, an internment site, and — very nearly — an amusement park. Hovedøya is the largest of Oslo's inner islands, forty hectares of forest, wildflower meadows, and layered history sitting eight hundred metres from the city centre. Most visitors come for the beaches. They should stay for the embedded history in the ruins and the soil and the sea.
The island's story divides neatly into three acts: the monastery period, the military period, and the municipal period. Each layer left its mark in stone, in place names, and in the city's collective memory.
The name
The name itself is a fossil. When the last ice age ended roughly ten thousand years ago, the land that had been pressed down by kilometres of ice began rising — and continues to rise, three to four millimetres per year. The highest point on what would become Hovedøya, about fifty metres above sea level, emerged first from the water. It looked like a head. In Old Norse, hovuð means head. The island was Hovuðey — Head Island.
Then came four centuries of Danish rule. Danes say hoved where Norwegians say hode, and after generations of Danish administration the name settled into its current form: Hovedøya. It has nothing to do with being the "main" island, despite what the modern Norwegian word hoved- (main, chief) might suggest. It is, and always was, simply the island shaped like a head.
Whether you say Hovedøya or Hovedøen remains one of Oslo's favourite minor quarrels.
Act one: The monks (1147–1532)
On 18 May 1147, Cistercian monks from Kirkstead Abbey in Lincolnshire arrived and founded a monastery dedicated to the Virgin Mary and Saint Edmund. They chose well. The sheltered valley between the island's two ridges offered good soil — former seabed tends to — and the location gave them control over access to Christiania's harbour without the distractions of city life.
The Cistercians were an austere order. Hovedøya was a silent monastery: the monks spoke only to God, six times a day at prayer. The single exception was the parlatorium, a small room where practical conversation was permitted. Walk through the ruins today and try to feel the weight of that silence — stone walls, damp cold, no human voice for years on end.
Their business model, however, was anything but quiet. Medieval theology held that sinners must burn away their transgressions in purgatory before entering heaven — a process that could last thousands of years. The monasteries discovered that generous donations could reduce the sentence. A wealthy farmer could donate his estate to the monastery in exchange for prayers on his death day, burial near the church wall, and the promise of a shorter wait. His heirs became tenant farmers on land their family had once owned.
Through this system, the Hovedøya monastery accumulated an estate of around 300–400 full farms. The nearby Nonneseter convent in Gamlebyen operated a similar scheme. Between the monasteries and the Church, much of the agricultural land in the Oslo region changed hands — not through conquest, but through theology.
The monastery's reach lives on in Oslo's geography. Maridalen, the valley running north from the city, derives from Mariae dalr — Mary's valley, named for the monastery's patron. Local pronunciation smoothed it into Merradalen before settling on the current form. Other remnants include Munkebekken (Monk's Brook), Klosterenga (Cloister Meadow), and Munkerud.
The end came in 1532. The abbot had backed the wrong king: Christian II, the deposed Catholic monarch who attempted to reclaim the throne with seven thousand soldiers camped at Kongshavn. When the attempt failed, the commandant of Akershus Fortress sent troops across to the island. The abbot was dragged from his bed on 21 January, hauled naked through the snow, and imprisoned. The monastery was looted and set on fire. Four years later, the Reformation made the destruction official: all Church and monastic property became Crown land.
The ruins that remain are among the most complete of any medieval Norwegian monastery. The portnerboligen — the gatekeeper's lodge — is the only surviving example in the country. Walk through it and you pass through the same doorway the monks used on their way to and from the harbour.
Act two: Warships and cannons (1640s–1814)
A century after the monks left, the island found a new purpose. Hannibal Sehested, Christian IV's son-in-law and Governor-General of Norway from 1642, established a shipyard on the shore to build warships for the Danish-Norwegian fleet.
The site was logical: direct deep-water access, proximity to Akershus Fortress, and — crucially — short transport distance from the oak forests of Ekeberg across the fjord. Oak was the essential material for warship construction, and Ekeberg had it in abundance.
The yard's most famous product was the Sophia Amalia, launched in 1650. Built by the English shipwright James Robbins under commission from Christian IV, she was designed to outgun the Sovereign of the Seas, England's most powerful warship. At nearly 52 metres in length, armed with 108 cannons and crewed by up to 680 men, the Sophia Amalia was among the largest naval vessels in the world at the time of her launch. She served the Dano-Norwegian navy for nearly four decades before being scrapped in 1687.
When the shipyard had consumed the available oak on Ekeberg, operations moved south along the coast to find new timber. What remained on Hovedøya were stone foundations — possibly including the slipway remnants still visible along the shore, though their exact identification is debated.
«England — previously Norway's most important trading partner — became the enemy overnight.»
The next military chapter came with the Napoleonic Wars. In August 1807, the British fleet bombarded Copenhagen for three days and seized the entire Dano-Norwegian navy. Denmark-Norway, left without a fleet, allied with Napoleon. England — previously Norway's most important trading partner — became the enemy overnight.
Akershus Fortress responded by fortifying Hovedøya with cannon batteries to defend the approach to the harbour. The guns were never fired in anger. The batteries visible today were reconstructed in 1990 as part of a restoration project, and at least one is reportedly still capable of being fired.
After 1814, when Norway entered a union with Sweden, King Karl Johan ordered four gunpowder magazines built on the island — two large, two small — as part of the fortress defences. They were whitewashed so they would be visible from the sea: a deliberate signal of strength in an era still haunted by the fear that another Napoleon might appear.
The bathing years (1914–1951)
From the late 1700s, a new idea drifted northward from Europe: that immersing the human body in water had curative powers. This was not about swimming, and emphatically not about hygiene. It was the water itself that was considered medicinal.
Men went first, and naked — giving rise to the Norwegian expression å hoppe i det (to jump into it). Women followed later, emerging from enclosed changing rooms into wooden enclosures that were lowered into the sea and raised again. Gradually, actual swimming developed, and inner Bjørvika became a bathing district with separate facilities for men and women.
In 1914, Kristiania municipality leased the lower part of Hovedøya from the military and built a substantial bathing complex in the sheltered bay. It had women's and men's sections, diving towers, and both free and paid facilities.
The peak came on 10 July 1932: 6,400 bathers on a single day. Over the thirty-seven years the facility operated, an estimated eight million visits were recorded. Dedicated bathing boats ran from the harbour, threading through the military zone that still occupied the upper island.
It ended in 1951. Industrial pollution from the factories along the Akerselva had destroyed the water quality in the inner fjord. The bathing operation moved to Langøyene, the two islands further south that Kristiania had purchased decades earlier and filled with garbage to create new land.
The clean-up of the Akerselva — driven by the Akerselva Miljøpark project championed by politician Sissel Rønbeck in the 1980s — eventually restored the fjord. Today, swimming has returned to Hovedøya's shores.
The German camp and after
During the Second World War, German forces established a camp of eleven barracks on the island, with signs warning that anyone approaching within 25 metres would be shot. Bomb shelter tunnels were dug straight through the rock. The officers' mess hall survives as "Klasse-kroa," still furnished with benches from the occupation.
What followed the liberation was, in some ways, worse. Under the guise of public health measures, women who had been in relationships with German soldiers were interned on the island for six months and set to work cleaning and clearing the former camp. After that, the barracks served as emergency housing for military families during the post-war housing shortage, lasting into the 1960s. When the buildings were finally demolished, contractors from Østfold hauled the materials south — and timber from Hovedøya's German barracks ended up in holiday cabins along the coast between Fredrikstad and Moss.
The island that almost became a theme park
When Oslo municipality finally took full control of Hovedøya, imagination ran wild. In 1954, the city council approved a plan for "Hovedøya Tivoli" — a full-scale amusement park with roller coasters, theatres, stages, and a bridge to the mainland. It was formally adopted, budgeted, and ready to go. Then it wasn't. The plan was shelved in 1979, apparently more through institutional drift than active cancellation.
An equally tantalising near-miss was the monastery museum. After archaeologist Gerhard Fischer excavated the ruins, a cloister walkway was reconstructed and display cases were prepared. The museum was essentially complete. But a dispute between the city and the state over whether an adjacent building should be demolished killed the project. The display cases were removed. The reconstructed walkway remains.
Walking the island today
Hovedøya is a nature reserve. Picking flowers is prohibited; all trees stand and fall where they are. The sheltered valley between the two ridges creates a microclimate roughly two degrees warmer than central Oslo, supporting several plant species at the northern edge of their range.
Near the old bathing beach, you can still find remnants of the 1914 facility — concrete foundations, rusted hardware. The military road that once kept civilians contained now serves as a walking path. The cannon batteries overlook the harbour approach, restored but peaceful. And in the silent ruins of the monastery, if you stand still long enough, you might catch a sense of what eight centuries of prayer sounded like when the only permitted sound was the wind.
Henrik Wergeland, the great 19th-century poet, once dreamed of planting the entire island with elm trees. Two survive — one standing, one fallen — the last remnants of Wergeland's forest.
The ferry from Rådhusbrygge (line B1) takes seven minutes. There is no entrance fee. Bring your own silence.
Further reading
This article is based on a guided walk led by author and guide Leif Gjerland on 20 May 2026, supplemented with historical sources. Gjerland is the author of Oppdag historien i Oslos øyrike. Some details from the oral tour have been fact-checked and adjusted where the historical record differs from the spoken narrative.
