The battle was fought between the Danish–Norwegian fleet and the British Royal Navy under the command of Admiral Sir Horatio Nelson, one of the most renowned naval commanders of his time.
The discovery was made by maritime archaeologists from the Danish Viking Ship Museum, which holds the national responsibility for archaeology on the seabed in eastern Denmark.
“We have found Dannebroge and the remains of those who never made it ashore after the battle.”
In recent weeks, maritime archaeologists have been excavating the shipwreck on the seabed of Copenhagen harbour. The investigation forms part of the archaeological work required in connection with the construction of the artificial island of Lynetteholm.
Fifteen metres below the surface, where visibility is almost zero, maritime archaeologists search metre by metre through the heavy silt. They follow traces that lead deep into Danish history. For right here, where Lynetteholm is set to be built, the dark waters conceal the remains of one of the most dramatic days in Denmark’s past. It was here that the ship of the line Dannebroge exploded and sank during the Battle of Copenhagen on 2 April 1801.
Investigations at Lynetteholm have now provided the archaeologists with tangible remains from the battle, and the hope is that the excavations in Copenhagen harbour can add new layers to the stories, says Otto Uldum, maritime archaeologist at the Danish Viking Ship Museum and leader of the excavation of the ship of the line Dannebroge:
“We are now gaining an archaeological body of sources on the Battle of Copenhagen, and that is something entirely new. It is not something that has previously been excavated or studied archaeologically.”
Facts: The Battle of Copenhagen, 2 April 1801
The Battle of Copenhagen was a naval battle fought between a British and a Danish fleet on 2 April 1801. The battle took place on the Copenhagen Roads, a shallow anchorage outside the city where large vessels could lie safely at anchor before entering the harbour.
For more than four hours, Danish sailors fought against a British force that was superior in every respect, commanded by Vice Admiral Horatio Nelson and equipped with one and a half times as many guns as the Danish fleet. Within just a few hours, the King’s Deep was transformed into an inferno of smoke, fire, and cannonballs, with almost unimaginable losses.
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“We have found Dannebroge, the flagship that exploded”
The archaeologists have been working on the excavation of the large shipwreck since the end of last year, and they are convinced that the remains belong to the ship of the line Dannebroge:
“We have no difficulty interpreting this as the remains of a large wooden warship. The dimensions of the timbers correspond exactly to the drawings of the ship that survive, and the dendrochronological dating matches the vessel’s year of construction in 1772. So we are stating this with a degree of certainty that borders on absolute,” says Otto Uldum.
The many finds in and around the wreck further support this conclusion, Otto Uldum explains:
“The area is littered with cannonballs and bar shot. And yes, we have found two cannons.”
225 years on: First archaeological investigations of the battle
The Battle of Copenhagen is well documented in history books and in contemporary national narratives. These accounts contain many stories of national sentiment and heroic deeds. Far less is written about the people who experienced—and died in—the brutal naval battle on 2 April 1801.
It is precisely for this reason that it is of particular significance that archaeological investigations are now, for the first time, being carried out on a wreck from the battle, explains Otto Uldum:
“This is the first time archaeological investigations have been undertaken that are directly linked to the Battle of Copenhagen. Although the battle is a central event in Danish history, no one, to my knowledge, has examined it archaeologically until now. That is actually quite remarkable.”
For the archaeologists, the discovery of Dannebroge offers an opportunity to make history tangible and to add a material dimension to the story:
“With the excavation, we gain something physical and concrete: yes, there is a large wreck and a substantial ballast mound—but it is Dannebroge’s ballast and Dannebroge’s ship timbers. These are the remains of an entire ship of the line, and it lies there in a place where we can now touch it,” says Otto Uldum.
Human remains: Archaeology gives the historic event a human presence
Among ballast stones and ship timbers, smaller traces are now beginning to emerge as well. These are objects connected to the crew and to the events on board—objects that are not represented in museum collections today:
“Museum collections most often contain the fine things. Officers’ uniforms and prestigious objects. We have found a number of personal belongings. Shoes and fragments of clothing, and various small items the sailors would have carried with them—clay pipes, uniform insignia, and weapons. And we have also found remains of one of the 19 people who are listed as missing,” says Otto Uldum.
Even before the excavation began, the archaeologists knew that they might encounter human remains in the wreck. After the battle, lists were compiled recording the numbers of dead, wounded, and missing. These lists show that 19 men from the crew of 357 were never found again, neither dead nor alive.
All other fatalities were recovered and recorded. The lists show that 53 people died on board Dannebroge, while three wounded men later died of their injuries at Søkvæsthuset, the naval hospital. Forty‑eight men are listed as “wounded, but still alive,” and 19 are recorded as “missing without further information”:
“We have found a lower jaw that is without doubt human, as well as several other bones, including ribs, which could very well be human. We are far from finished sorting and analysing the material, but we are bringing everything up,” explains Otto Uldum.
A new source for an event that shaped Denmark
With the archaeological investigation of Dannebroge, we are given the opportunity to look at an event that has shaped Denmark’s history and sense of identity through new eyes.
But one might ask why it is important to excavate a history we think we already know.
“First of all, we need to leave room for surprises. Secondly, there is the consideration of the status of the find. Precisely because this is such a famous event, it requires an extra level of scrutiny,” says Otto Uldum.
The Battle of Copenhagen is part of our national narrative, written into books, painted on canvases, and embedded in our culture. For that reason, every single find is—according to Otto Uldum—an important source for understanding our shared history. And this means that the excavation of Dannebroge is not only about archaeology, but about an event that has shaped Denmark’s history and self‑understanding:
“Every time we say even a little something about a shoe or a bone, it matters just a bit more, because this is actually the Battle of Copenhagen.”
According to the archaeologist, the archaeological finds contribute a dimension that written sources and the museums’ collections of prestigious objects do not contain. These are not objects created to commemorate or impress. They are the remains of the majority, offering broader perspectives and new sources for a history we may think we already know:
“Statistically, it is easier for us to find something that belonged to the ordinary sailor. We have found more remains of shoes from common gunners than of the officers’ fine boots—and you have to be lucky to find those, because there weren’t many such boots on board, but there were an awful lot of those gunner’s shoes. In that sense, what we find is probably more representative—socially speaking,” Otto Uldum concludes.
Facts: The ship of the line Dannebroge
Name:Dannebroge
Type: Danish ship of the line (later reduced and re‑rigged as a blockship)
Place of construction: Nyholm, Copenhagen
Designer: F. M. Krabbe
Year of construction: Begun in 1770. Launched in 1772. Commissioned into the navy in 1774
Length: approx. 48 metres (158 feet)
Beam: approx. 13.3 metres (42.5 feet)
Armament (original):
60 guns at commissioning in 1774
(When converted into a blockship in 1801, the vessel’s armament was modified and partly removed.)
Crew:
Rated for 559 men in active service
As a blockship in 1801, approx. 357 men at the beginning of the battle
Role in the Battle of Copenhagen:
Deployed as a blockship and used as the flagship of Commander Olfert Fischer from 27 March 1801. Caught fire during the battle, drifted northwards, and exploded shortly after 4 p.m. on 2 April 1801.
The Battle of Copenhagen, 2 April 1801
Copenhagen harbour lies still. But only for a moment. A vast British fleet, led by the famous Vice Admiral Nelson, prepares to attack the city. The ships have been lying in the Øresund for several days, and now they are ready to strike the capital. The British fleet enters the King’s Deep from the south with a total of 39 vessels armed with heavy guns. Twelve of them are large ships of the line, whose many cannons allow them to sail one after another in line, forming a moving wall of naval artillery aimed at the enemy. Behind them follow smaller frigates and heavy bomb vessels. Altogether, the British bring 1,270 guns into the battle.
In Copenhagen, there has been intense activity since mid-March, when the first rumours of an impending attack began to circulate. And just a few days ago, a faint thunder of cannon fire was heard. It was the British fleet forcing its way past Kronborg. Now there is no doubt. The British are on their way.
The survival of the realm is at stake, and it is not only soldiers who answer the call. Fishermen, craftsmen, and farmers volunteer as well. Some receive only a few hours of training before the battle.
Just outside the harbour—on what is known as the Copenhagen Roads, a shallow area where, in peacetime, large merchant vessels can safely anchor before sailing into port—the Danish defensive line is now positioned.
It consists of a chain of old Danish ships of the line laid out as floating fortresses, the so‑called blockships. Stripped of rigging—no ropes or tall masts—but laden with cannons. Between the large, old ships lie barges and timber rafts packed with guns. All vessels in the line are secured with massive anchors. The Danish defence cannot manoeuvre; it can only hope to hold its ground with its 833 guns against the enemy’s 1,270.
At the centre of the Danish defensive line lies the warship Dannebroge, and this is no ordinary vessel. From here, the Danish commander Olfert Fischer is to lead the more than 6,000 men who make up the Danish defence.
At 8:00 a.m., the British vice admiral gives the signal: prepare for battle. And at 9:45 a.m., the attack begins. The British ships glide into the King’s Deep from the south.
On quays, balconies, and rooftops, thousands of Copenhageners stand watching. They look on. They wait.
At 10:15 a.m., the first Danish shot is fired. A thunderous boom—and then an inferno. Soon the King’s Deep is a hell of smoke, fire, and flying splinters that tear through the air, piercing and maiming the soldiers.
Many spectators are disappointed, as the smoke is so dense that they cannot see the course of the battle.
The fighting quickly develops into a brutal, bloody, and close‑range struggle, with ships of the line lying only a few hundred metres apart, firing broadside after broadside at each other.
Dannebroge is the primary target of Nelson’s attack and is bombarded by two British ships of the line. The situation on board soon becomes desperate. Shot sweeps the upper deck clear of both guns and crew. There are many wounded and dead. The ship is also struck by incendiary shells, and fires break out on board. The crew now fights both the flames and the enemy’s gunfire.
The large ship of the line Sjælland is riddled with shot and drifts like a ghost ship through smoke and fire, while other vessels drift towards the coast. Prøvestenen, Wagrien, Jylland—one by one they fall. Dannebroge stands in flames. At first, the British cannot hit the low-lying gun barges—they simply fire too high—and the Danish gun barges inflict serious damage on the British line. But as the Danish ships are gradually weakened, the British guns can be lowered, and now the gun barges too come under heavy fire.
Further out in the sound lies Admiral Parker with his ships. Through the thick smoke, he cannot see how the battle is going, and around 1:00 p.m. he fears the battle is lost. He therefore sends a signal ordering an immediate withdrawal. But Vice Admiral Nelson ignores the order with the famous words: “I have only one eye—I have the right to be blind sometimes.” He raises his telescope to his blind eye and says, “I see no signal,” and continues the fight.
The sound of Danish cannon fire becomes increasingly sporadic, and by 2:00 p.m. the Danish line is close to collapse. Several Danish ships have been captured, and their crews taken prisoner. To force the Danes to surrender, Nelson sends a threatening letter to Crown Prince Frederik, warning that he will set fire to the Danish ships—with the wounded sailors still on board—unless the fighting stops.
At 4:00 p.m., a ceasefire is agreed, and the battle is over. In just a few hours, the Copenhagen Roads have been transformed into a sea of wreckage and dead. Dannebroge drifts northwards, and at around 4:30 p.m. the ship explodes with a deafening roar that can be heard across the entire city.
The casualties are overwhelming. The British lose approximately 255 men, with more than 700 wounded. But the Danish losses are even more devastating. The lists record that 370 men die during the battle, and 665 wounded are taken from the ships to the naval hospital, Søkvæsthuset. In the days that follow, more than 100 men die of their injuries. But not all make it ashore. At least 200 Danes are missing, and along the coast of the Øresund both Danish and British bodies wash ashore after the battle. No one knows with certainty the full death toll of the Battle of Copenhagen.
Facts: Maritime archaeological investigations at Lynetteholm
Ahead of the construction of the artificial island of Lynetteholm, large parts of the seabed in Copenhagen harbour have been investigated due to known maritime archaeological potential.
The work is carried out by the Danish Viking Ship Museum, which holds national responsibility for maritime archaeology in eastern Danish waters. The investigations are financed by By & Havn in accordance with Danish heritage legislation.
Since 2020, maritime archaeologists have conducted extensive surveys, diver inspections, sediment sampling, and full excavations in the area. This has included the discovery and recovery of several previously unknown shipwrecks, among them the world’s largest 15th‑century cog and, most recently, the ship of the line Dannebroge from the Battle of Copenhagen in 1801.
All recovered material is documented using 3D scanning, surveying, and photographic recording before construction work continues.
The archaeological investigations are expected to be completed in spring 2026.