While looking for Swedish volunteers in an old paper I stumbled upon probably the first report in our press about the first German steel helmet. Be prepared for an amusing caption from 1916...
This photograph was published in the Swedish weekly Hvar 8 Dag on September 10, 1916:
German troops wearing the first ever German steel helmet, the M1916. Before these were issued, the German soldier wore a spiked helmet (Pickelhaube) made of boiled leather.
Now, the original caption in my translation: "THE NEW GERMAN STEEL HELMET. Within several German regiments the steel helmet has been introduced experimentally. Such helmets have long been present in English and French trenches. The German one has, quite evidently, a different, not that elegant shape, in comparison to its predecessors."
By the way, I´d like to recommend the English language Wikipedia article about the history of the German steel helmet. If you want to know more, see "External links" at the bottom of the Wikipedia page.