Fortifications of Copenhagen (17th century)

Bastioned Fortifications of Copenhagen
Copenhagen
Map of Copenhagen Anno 1728 with fully developed fortifications
Type	Citadel
Site information
Open to the public	Yes
Condition	Mostly dismantled, parts well-preserved
Site history
Built	1606-26
In use	-1870
Materials	earthworks, masonry

The fortifications of Copenhagen underwent a comprehensive modernization and expansion in the 17th century. The project was commenced and was largely the masterplan of Christian IV in the early 17th century but was continued and completed by his successors. The new fortifications relied on the existing, medieval fortifications of the city but the fortified area was extended and a defensive ring around the city completed particularly with new edifices facing the sea. The ring fortification consisted of four bastioned ramparts and an annexed citadel as well as various outworks.

Though largely developed to a final form in the 17th century, the fortifications remained in use until the second half of the 19th century, when they finally, a long time overdue, were decommissioned. Today only the Christianshavn Rampart and the citadel Kastellet remain intact, while the rest of the fortifications were dismantled in the years after its demise. The grounds were to a large extent laid out as parks, forming a green band around the city centre still known as the Fortification Ring, as well as for construction of a number of public buildings, including the new Copenhagen City Hall as well as a number of museums.

Christian IV's modernization of the fortifications of Copenhagen commenced in 1606 and would take 20 years to complete. The course of the medieval fortifications was kept but Slotsholmen was now incorporated into the complex. A large bastion in masonry was constructed on its southwestern tip and connected to Vestervold by a vaulted dam known as Løngangen. In the same time, Østervold was taken around parts of Bremerholm to meet the sea.

A total of 12 bastions were constructed and just outside the entire fortification a moat was dug. Due to topographical variations in the terrain, it was constructed as a series of basins, separated by dams, to solve the problem of variations in the terrain. The uppermost basin was fed by water from Peblingesøen. The Western and Northern City Gates were also renovated and given tall spires and a new Eastern City Gate was built.