Danish M1923 helmet

Danish soldiers wearing M/23 helmets at an AA gun

Following World War I the Danish government fell into line with other industrialized nations and began to equip their soldiers with steel helmets. This new trend emerged from the trenches of World War I where steel helmets greatly reduced casualties. The Danish Military accepted plans for the helmet in 1923 from Army Captain H. E. Johnsen and engineer G.A.P. Willadsen-Nielsen.[1] The helmet saw combat during the German invasion of Denmark, Operation Weserübung, on April 9th 1940, and very limited use with the Danish volunteers in Finland during the Winter War.[5] It is uncertain if the volunteers brought the helmets back to Denmark in 1940, or if they remained in Finland.

Following the end of the war in 1945, Denmark gradually phased out the M/23 in favour of the M/48 steel helmet, which was modelled after the American M1 helmet. This move coincided with many other NATO members who adopted the same design. The M/23 is unique in that it was never exported internationally making Denmark the only country ever to use it. This contrasts with other helmets of the era such as the French Adrian helmet and the British Brodie helmet, which were widely distributed around the world. Moreover, this helmet's distinctive appearance makes it easily recognizable from other interwar steel helmets.

Discarded Danish weapons and helmets following the German invasion

The M/23 was made from a single piece of Swedish steel and was produced in both military and civilian versions.[3] The military version contained either an Army or Navy emblem on the front, depending upon which branch it was issued to. From the 1930s the helmets were covered with textured grey or a light shade of khaki paint.[6] The inside of the helmet was equipped with a leather chin strap and liner consisting of eight flaps.[2] On the rear of the M/23 a hanging slot can be seen towards the bottom.

During the Second World War a number of different versions of civilian M1923 helmets were made. They are among collectors known as the M1941.[7] It is plausible that A/S Glud og Marstrand made the M1941, as they already had the machinery tooled for the production of the army helmets. The civilian version was issued to various non-military organizations such as, police, fire departments, and the press. The civilian version did not have a decal on the front, and was made from lighter steel. It had a lower quality liner and chin strap.[7] Unlike the military version it remained in service with these groups and the Civil Defence after the war.[8]