First introduced in 1915 and named for General Adrain, the Casque Adrian was the first pattern stell helmet. It was aopted as the standard issue helmet of the French army by 1917. With millions of French troops engaged in trench warfare, head wounds became a significant proportion of battlefield casualties. Made of lightweight steel and weighing only 1 lb., 11 oz. it was lighter than the contemporary British Brodie helmet and the German Stahlhelm.

Initially issued to infantry, its modified versions were also issued to cavalry and tank crews. It was also used by some of the American divisions fighting in France and served as the basic helmet of many armies well into the 1930s.

The Pickelhaube (German for picket or point, haube for bonnet) was a Prussian spiked helmet worn by the German military, firefighters and police during the 19th century. Aside from the spike, perhaps the most recognizable feature of the Pickelhaube was the ornamental front plate, which denoted the regiment’s province or state. The most common plate design consisted of a large, spread-winged eagle, the emblem used by Prussia. Bavaria, Württemberg, and Baden—the other German states used different plate designs.

During World War I, it was soon discovered that the Pickelhaube did not measure up to the demanding conditions of trench warfare. The leather helmets offered virtually no protection against shell fragments and shrapnel. Furthermore, the spike often showed above the top of the trench, thus revealing the location of the soldiers inside the trench.

The term Stahlhelm refers both to a generic steel helmet, and more specifically to the distinctive (and symbolic) German design. The M1916 was the first production model of the Stahlhelm design and was developed by Hauptmann Friedrich Schwerd, a professor at the Hanover Technical Institute.

The helmet was first issued to the 1st Assault Battalion for evaluation in December 1915. In February of 1916 it was introduced in small numbers to the front line troops engaged in the battle of Verdun. The resulting reduction in the number of head wounds suffered by the soldiers lead to mass production of the M1916 Stahlhelm and the army soon began replacing the traditional leather Pickelhaube. The Imperial German army wore the Stahlhelm helmet from 1916 through the end of the war.

The Brodie helmet was a steel helmet designed and patented in 1915 by John L. Brodie. It was also called the shrapnel helmet or Tommy helmet and colloquially, as a “tin hat.” In the United States it was known as a doughboy helmet.

The British Army first utilized the helmet in September 1915. But it was not until the spring of 1916 that the helmet began to be issued to the troops in large numbers; it was first used in battle in April at the Battle of St Eloi. Troops from other countries in the British Empire also used the Brodie helmet, as did the United States Armed Forces when they entered the war in 1917.