The embankments, bastions and moats that defended Copenhagen were extended and rebuilt in the late 17th century. To enter or leave the city there were four gates that were built or rebuilt as part of that work.
Vesterport, the west gate, was at the end of what is now Frederiksberggade - the position of the gate was in the centre of what is now Rådhuspladsen, the large square in front of the present city hall, but then was a much smaller open area that was the Hay Market. The north gate, Nørreport, was at the end of Frederiksborggade, close to the present Nørreport station, and the east gate, Østerport, was then just beyond the Nyboder houses, close to what is now the open area at the entrance to Østerport railway station. All three gateways were demolished in 1857.
Embankments and bastions around the south side of the city survive although the south gate, Amagerport, was also removed in the 1850s.
Although the gateways do not survive there are prints and drawings of the gates and some very early photographs. The engravings show that the outer sides of the gates were ornate with pilasters, niches, pediments and carved stonework including coats of arms and dates.
The gateways were approached by timber bridges so, presumably they could be destroyed before an attack. The bridges were also set at an angle and there was a break on the approach on an intermediate island bastion so that attackers would not have a direct line of fire through the archway of the gates.
Each gate had a long internal barrel-vaulted tunnel through the earth embankment with an inner gateway facing the approach from the city. These inward facing archways were all much simpler in design.
All the gateways had guard houses both inside and on the outer side beyond the moat.
Old maps provide crucial evidence about the position of the gateways and for the form of less substantial structures such as the bridges and the guard houses. A series of surveys completed by Christian Gedde in the 1760s is particularly important for the map he produced is given the appearance of an aerial view. Below is a detail of his map showing the Amagerport or south gate.
Although the city gates were demolished more than 150 years ago, it is still possible to get a strong impression of how they worked and what they looked like from the two surviving gates at the Kastellet, the fortress that was constructed in the 1660s to defend both the north part of the city and the approach to the harbour.