What helmet typically associated with the Prussian Army was replaced by a steel helmet during World War I?
Stahlhelm: Stahlhelm (plural "Stahlhelme") is German for "steel helmet". Stahlhelm:  The Imperial German Army began to replace the traditional boiled leather Pickelhaube (spiked combat helmet) with the Stahlhelm during World War I in 1916.
i don't know