At the beginning of World War I, none of the combatants were issued with any form of protection for the head other than cloth and leather caps, designed at most to protect against saber cuts. When trench warfare began, the number of casualties on all sides suffering from severe head wounds (more often caused by shrapnel bullets or shell fragments than by gunfire) increased dramatically, since the head was typically the most exposed part of the body when in a trench. The French were the first to see a need for more protection—in late 1915 they began to issue Adrian helmets to their troops. The British and Commonwealth troops followed with the Brodie helmet (a development of which was also later worn by US forces) and the Germans with the "Stahlhelm".