Pickelhaube

The Pickelhaube (plural Pickelhauben; from the German Pickel, "point" or "pickaxe", and Haube, "bonnet", a general word for "headgear"), also Pickelhelm, was a spiked helmet worn in the nineteenth and twentieth centuries by German military, firefighters, and police. Although typically associated with the Prussian army who adopted it in 1842-43, the helmet was widely imitated by other armies during this period.

The Pickelhaube was originally designed in 1842 by King Frederick William IV of Prussia, perhaps as a copy of similar helmets that were adopted at the same time by the Russian military. It is not clear whether this was a case of imitation, parallel invention, or if both were based on the earlier Napoleonic cuirassier. The early Russian type (known as "The Helmet of Yaroslav Mudry") was also used by cavalry, which had used the spike as a holder for a horsehair plume in full dress, a practice also followed with some Prussian models (see below).

Frederick William IV introduced the Pickelhaube for use by the majority of Prussian infantry on October 23, 1842 by a royal cabinet order. The use of the Pickelhaube spread rapidly to other German principalities. Oldenburg adopted it by 1849, Baden by 1870, and in 1887, the Kingdom of Bavaria was the last German state to adopt the Pickelhaube (since the Napoleonic Wars, they had had their own design of helmet, called the Raupenhelm (), a Tarleton helmet). Amongst other European armies, that of Sweden adopted the Prussian version of the spiked helmet in 1845 and the Russian Army in 1846 (although see above for Russian/Prussian controversy).

...
Wikipedia