Fortification of Copenhagen

The fortification of Copenhagen , the capital of Denmark , can be divided into three periods:

the medieval city wall with early modern reinforcement (11th / 12th century to 1606)
the bastion fortification of the early modern period (1606–1870)
the fortifications of the late 19th and early 20th centuries (1886–1916), built mainly of concrete .

In addition, there were the coastal batteries to repel attacking ships, which were mainly built in the second half of the 19th century and the beginning of the 20th century.

The medieval city wall

A first, small-scale fortification of ramparts and moats was probably built in the middle of the 12th century, and a little later the castle on Slotsholmen (today under Christiansborg Palace ). With the growth of the city, a new city fortification consisting of ramparts and moats was built in the first half of the 13th century, which was reinforced in the following centuries by a wall and towers. At the beginning of the 16th century, semicircular barbican had been laid out in front of the gates.

The bastionary fortification 1606–1624

From 1606 to 1624, under Christian IV , Copenhagen was surrounded by a new bastion fortification, which largely followed the course of the medieval city wall. 1618–1623 the new district Christianshavn was also fortified. A little to the north was the defensive hill Sankt Annae Skanse , built from 1627 , from which the citadel Kastellet developed. 1647–1658 the north corner of the wall was connected with the Sankt Annae Skanse by a new and much stronger wall, which gained space for new city quarters between the defensive hill and the previous city. From 1662 to 1666 the Sankt Annae Skanse was expanded into a spacious citadel. In 1667–1670 the other walls were reinforced and provided with much larger bastions. 1682–1692 the walling around Christianshavn was extended to the north to protect the harbor. This gave the bastionary city fortifications their final dimensions. It was finally abandoned in 1870 and largely demolished in the west, while Kastellet and the Christianshavn enclosure are very well preserved.

The new fortifications made of concrete (1886–1916)

Aerial view of Copenhagen with Vestvolden (red line), the Siegfried Line and the floodplains (blue areas)

In 1886, when explosive ammunition was developed and numerous European fortresses were outdated due to their greater destructive effect, work began on a completely new fortification of Copenhagen, which was one of the first European fortifications to take into account the requirements of explosive ammunition. On the land side, this consisted of three elements;

the 15 km long Vestvolden ("Westwall") (1888-1892)
to the north adjoining flood areas, for which canals and sluices were built, which were defended with 8 smaller and one larger battery
6 forts in front of the floodplains
3 ranged batteries between the forts and the floodplains.

Vestvolden (1888-1892)

Vestvolden (The "West Wall") is a 15 km long linear rampart with a wet ditch in front, which starts at the sea in the south and leads slightly curved to Utterslev Mose . On the wall there is a parapet for infantry and 15 artillery batteries were installed and eight further batteries were prepared. Various magazines are housed at the foot of the wall. The 16 m wide and up to 2.5 m deep ditch is sloping on both sides and is flanked by a total of eleven single and four double capons (better casemates). The simple capons are built into short flanks and are slightly withdrawn and thus withdrawn from direct artillery fire. The double ones are built on small triangular islands in the form of ravelins in the ditch and the front side is completely sloped in earth. A 7.5 cm cannon and two double-barreled 8 mm machine guns were installed for each direction of fire. Seen from the side and their function, these capons are strongly reminiscent of the casemates of the Maginot Line, built 40 years later in France. In 1920 Vestvolden was abandoned as a fortress.

The six country forts

To the north of Vestvolden there are flood plains and a series of six forts in front of them, which connect in an arch to the Öresund . Just beyond the forts, three permanent ranged batteries have been set up. It is noteworthy that the first two fortifications Garderhøj Fort and Lyngbyfortet were built to a large extent from private donations collected by the association Den frivillige Selvbeskatning til Forsvarets Fremme (The voluntary self- taxation in support of the defenses). All forts are armed with artillery and machine guns under armored domes. Garderhøj Fort, the oldest fort, has a number of structural features, including a rectangular floor plan. The five other forts have a triangular floor plan, the trenches are sloping and are painted on both fronts from a double trench stroke in the Contrescarpe . Instead of the escarpe there is an obstacle grid. The armored towers are erected over the casemated Kehl barracks , which serve as accommodation. Only the youngest fort, the Taarbæk Fort , has a postern under the moat to access the moat, the two oldest Garderhøj Fort and Lungbyfortet have posternes that end frontally at the Escarpe, from where the moat had to be crossed openly. In the case of the other three forts, the trench could only be reached via the front ditch. The throat was coated with casemates in the recessed flanks of the throat barracks.

Garderhøjfort (1886-1892)

The oldest fort differs from the other forts in its rectangular floor plan, the brick escarps and contrescarps, the small caponier ( throat case ) to coat the throat side and the additional casemates for infantry built into the contrescarpe . The only fort also had its own battery block the center, in which part of the armored turrets were. It is armed

1 large armored rotating dome with two 15 cm cannons on the Kehlkaserne
2 anti-tank turrets with a 5.3 cm cannon each on the Kehlkaserne
2 armored rotating domes, each with a 15 cm cannon on the battery block
2 armored rotating domes, each with a 7.5 cm cannon
2 anti-tank turrets with 8 mm machine guns above the postern near the shoulder points
4 4.7 cm cannons for trench defense
9 double-barreled 8 mm machine guns or ten-barrel Gatling for trench defense.

Garderhøjfort was closed in 1920 and can be visited on guided tours.

Lyngbyfortet (1888-1892)

Lyngbyfortet was armed with

2 armored rotating domes, each with two 15 cm cannons
3 armored rotating domes with a 15 cm cannon each
2 anti-tank turrets with a 7.5 cm cannon each
1 anti-tank turret with a double-barreled 8 mm machine gun above the postern in the front
4 4.7 cm cannons for trench defense
6 double-barreled 8 mm machine guns for trench defense.

Abandoned in 1920.

Fortunfortet (1891-1893)

Fortunfortet was equipped with

4 anti-tank turrets, each with a 7.5 cm gun
4 7.5 cm cannons for trench defense.

Abandoned in 1920

Gladsaxefortet (1892-1893)

Gladsaxefortet consisted of

4 anti-tank turrets, each with a 12 cm howitzer
4 12 cm howitzers for trench defense.

Abandoned in 1920.

Bagsværdfortet (1892-1893)

Bagsværdfortet consisted of

4 anti-tank turrets, each with a 12 cm howitzer
4 12 cm howitzers for trench defense.

Abandoned in 1920.

Taarbæk Fort (1913-1916)

The youngest fort, Taarbæk Fort , was only a partially successful combination of land fort and coastal battery. The location did not offer optimal observations, so a 33 m high observation tower was built for better observation. The fort had

4 29 cm cannons towards the lake
2 anti-tank turrets, each with a 12 cm howitzer
3 armored turrets with 2 MG each
3 3.7 cm cannons for trench defense
9 MG for trench defense.

Taarbæk Fort was abandoned in 1937 and covered with earth in 1969.

The 3 ranged batteries

Tinghøj Batteri (1887–1888)

This large battery had a central casemate block

2 anti-tank turrets each with a 10-barrel 8 mm machine gun.

This was followed by batteries on both sides

6 15 cm cannons
2 12 cm cannons.

Abandoned in 1920.

Buddinge Batteri (1888–1889)

It was an open battery for

6 12 cm cannons

Abandoned in 1920.

Vangede Batteri (1887–1888)

This large battery had a central casemate block

2 anti-tank turrets each with a 10-barrel 8 mm machine gun.

This was followed by batteries on both sides

9 12 cm cannons

Abandoned in 1920.

The batteries behind the flood systems

Gentofte Batteri (1888)

Gentofte Batteri an open battery for

4 9 cm cannons.

Abandoned in 1920.

Bernstorff Batteri (1888)

Bernstorff Batteri an open battery for

4 9 cm cannons.

Abandoned in 1920.

Dam Batteries I – IV (1888)

These four batteries were supposed to secure the dams in the floodplains and each had two open beds for mobile armored towers with a 53 mm cannon or for double-barreled machine guns.

Ordrup Krat Battery East and West (1887)

The two batteries of Ordrup Krat (Ordrup Krat Batteri) were designed as flanking, casemated batteries similar to the Doppelkaponnieren (double casemates) of Vestvolden, were used to paint the dams and were each equipped with

2 7.5 cm cannons
2 4.7 cm guns.

Abandoned in 1920.

Christiansholms Batteri / Fort (1887-1892)

The larger battery complex of the Christiansholms Batteri consisted of a central, small, triangular casemated fort made of concrete, which was surrounded by a wet ditch. The throat ditch continued on both sides, on each of which an open battery lay behind the ditch. These were stocked with

8 15 cm cannons
9 9 cm cannons.

The central fort had

3 armored rotating domes with a 15 cm cannon each
2 anti-tank turrets each with a 10-barreled 8 mm machine gun
2 4.7 cm cannons for trench defense
2 8 mm machine guns for trench defense

Abandoned in 1920.

The coastal defense

Hvidøre Batteri (1892)

The Hvidøre Batteri consisted of

4 17 cm cannons

Charlottenlund Fort (1886–1888)

The large coastal battery of the Charlottenlund Fort is surrounded by a wet moat and rampart. The original armament consisted of

2 35.5 cm cannons
2 15 cm cannons
2 4.7 cm guns
4 4 pounder muzzle loaders

The battery was rebuilt in 1910-12 and was now equipped with

12 29-cm howitzers that are still in the fort today,
4 12 cm cannons
1 4.7 cm anti-aircraft gun
3 3.7 cm cannons.

The battery was abandoned in 1932 and is now used as a camping site.

Fortress island Middelgrundsfortet (1890-1894)

Middelgrundsfortet , a large, artificial fortress island in 7.5 m deep water, played a central role in coastal defense.

5 30.5 cm cannons
12 17 cm cannons
6 12 cm cannons
7 3.7 cm cannons.

After the Second World War they were installed

4 10.5 cm anti-aircraft guns
9 twin 40mm cannons
7 20 mm automatic cannons

From 1968 six-launching of merchandise Hawk - aircraft missiles installed. Middelgrundfort was closed in 1984.

Flakfortet fortress island (1910-1916)

The armament of the much smaller fortress island Flakfortet consisted of

4 29 cm howitzers
6 21 cm cannons
4 12 cm cannons
5 7.5 cm cannons
2 4.7 cm guns
4 3.7 cm cannons

In the 1950s the armament was changed to

4 German 10.5 cm anti-aircraft guns
6 twin 40mm cannons
8 20 mm automatic cannons

Abandoned in 1968.

Kalkbrænderi Batteri I (1864)

The Kalkbrænderi Batteri I consisted of

4 drawn 36 pounders

Abandoned and demolished in 1881.

Kalkbrænderi Batteri II (1880–1881)

4 35.5 cm

Abandoned in 1909, demolished in 1915.

Trekroner Fort (1858, 1898–1899)

Instead of the fort in front of (today) the port entrance, a "fort" already existed in 1713–1731, consisting of 10 ships set on the ground that formed a 5/6 circle. 1787–1827 a regular polygonal fort was built, which was open to the throat and housed a small harbor. In 1801 it was armed with

9 36 pundits
59 24 pounders
3 150 pound mortars

Trekroner Fort was fundamentally rebuilt in 1858, with some of the guns being housed in armored casemates. It was armed with

8 towed 84 pounder muzzle loaders
4 pulled 30 pounder muzzle loaders
21 smooth 84 pounder muzzleloaders
3 168 pound mortars.

The fort was rebuilt in 1898–1899, including closing the armored casemates and taking them out of use. In 1894 the assembly consisted of

14 29 cm cannons
2 24 cm cannons
6 17 cm cannons
11 15 cm cannons
8 4.7 cm cannons
2 rifled 29 cm muzzle loading cannons
5 84 pounder muzzle loaders
7 smooth-barreled 24-pounder muzzle-loaders

In 1920 the armament only consisted of

2 24 cm cannons
6 17 cm cannons
7 15 cm cannons
2 7.5 cm cannons
2 4.7 cm guns

Trekroner was abandoned as a fort in 1932. Anti-aircraft guns were installed during World War II.

Lynetten battery (1858)

Lynetten is a battery located on an artificial island north of the end of the bastionary fortifications around Christianshavn. Today it is connected to Amager and was built in 1767. In 1858 it was modernized and equipped with

5 rifled 84-pounder muzzle-loading cannons
18 rifled 30-pounder muzzle-loading cannons
3 smooth-barreled 84-pounder muzzle-loading cannons
1 168 pound mortar

1886-1894 the armament was changed to

29 cm howitzers
3 4.7 cm cannons, also remained
18 rifled 30-pounder muzzle-loading cannons

It was still in 1918

4 15 cm cannons
1 7.5 cm cannon
2 4.7 cm guns

In 1962 the battery was abandoned.

Mellem Fort (1860–1863)

The armament initially consisted of

4 84 pounder guns
10 36 pounder guns
2 168 pound mortars.

In the 1880s it was switched to

2 35.5 cm cannons
4 24 cm cannons
3 4.7 cm cannons

Mellem Fort was abandoned in 1932 and demolished in 1966.

Prøvestenen (1859–1863)

As early as 1713–1777 and 1801–1828 there were successive batteries under this name, which were built from three aground ships. The actual fort was built in 1859–1863 on an artificial island made of granite and is one of the earliest concrete fortifications. Prøvestenen had guns in a casemated floor, on which other guns stood in open beds. The armament consisted of

10 84-pounder muzzle-loading cannons
12 rifled 30 pounder muzzle-loading cannons
34 smooth-barreled 84 pounder muzzle-loading cannons
3 168 pound mortars.

Around 1890 the assembly consisted of

6 29 cm howitzers
16 17 cm cannons
8 4.7 cm cannons
2 smooth-barreled 12 pounders.

It was abandoned in 1922 and demolished after 1934.

Strickers Batteri (1860, 1875–76)

The open Strickers Batteri , first built in 1801, were renewed in 1860 and 1875–76 and were armed with

2 29 cm guns, the

1882 by

2 35.5 cm guns were replaced.

The battery was demolished in 1954.

Kastrup Battery / Fort (1886–1887)

The battery was surrounded by a wet ditch and had

4 30.5 cm cannons
2 15 cm cannons
2 4.7 cm guns
2 4-pounder muzzle-loading cannons for trench defense
2 double-barreled 8 mm machine guns for trench defense

In the First World War were also set up

2 7.5 cm cannons
3 3.7 cm cannons in place of the muzzle loaders

Kastrup Fort was abandoned in 1922.

Dragør Fort (1910-1915)

4 35.5 cm cannons from the Charlottenlund and Kalkbraenderi batteries
4 17 cm guns from Fort Provestenen
4 12 cm cannons
2 7.5 cm cannons
1 4.7 cm gun

In 1998 the Dragør Fort was still in use and equipped with

2 3-inch cannons that were deployed in the early 1980s -

Kongelundsfortet (1914-1916)

4 29 cm howitzers from the Lynetten battery
4 7.5 cm cannons
2 4.7 cm guns

In 1938 the Kongelunds Batteri , now Kongelundsfortet , was rebuilt and included

4 15 cm cannons armed.

It was only closed in 1982.

Avedøre Batteri (1892)

Avedøre Batteri was at the south end of Vestvolden and was equipped with

8 29 cm howitzers

The battery was released in 1922.

Barakke Batteri (1904)

Barakke Batteri was on the island of Saltholm and was abandoned in 1932, the armament consisted of

2 4.7 cm guns

Saltholm Battery (1910-1912)

The battery was on the island of Saltholm , was also abandoned in 1932 and was equipped with

2 7.5 cm cannons
8 MG

Mosede Batteri (1913-1916)

The Mosede Batteri , today Mosede Fort , consisted of

6 12 cm howitzers
4 7.5 cm anti-aircraft guns
4 3.7 cm cannons in the capons for trench defense

Abandoned in 1947.

literature

Peter Thorning Christensen, Bi Skaarup, Dahl Björn Westerbeek: The Fortifications of Copenhagen . A Guide to 900 Years of Fortification History. Skov- og Naturstyrelsen, København 1998, ISBN 87-7279-110-1 (Danish: Guide til Københavns befæstning: 900 års befæstningshistorie . Translated by Donald Bryant).