The old fortifications around Copenhagen dating from
the 17th century were demolished
during the the years from
1872, and the constructions of a new defence
system was commenced in 1885.
The old naval and coastal forts were modernized, and a number of new
forts north of the capital were constructed together with a new defence
line "Vestvolden" (The Western Enceinte) about 12 km south west of
Copenhagen. The shore defences also received some new naval and coastal
forts and batteries.
At the time of its construction the defence line was a worthy opponent
for any aggressor with new and modern 15 cm artillery, mitrailleuses and
machine guns which were hidden behind concrete walls.
But military developments went very fast at the time, and just 20 years
after its construction, the defen-ce line was out of date from a
technological point of view. Also it was too close to the capitol. The
fortifi-cations needed a lot of manpower to be effective. All the 50.000
men that were enlisted to protect Danish neutrality in 1914, were
deployed around Copenhagen.
As a result of this knowledge, a political agreement from 1909 became
the basis for a new defence line 30 km west of the city - the Tune
stronghold between the Køge Bugt (Koge Bay) and Roskilde Fjord (the
Fjord of Roskilde). This line is the narrowest point on the island of
Sjælland. The construction work started just after the outbreak of
World War I.
In 1920 the defence lInes of Copenhagen were abandoned.