The last time cavalry of both sides wore a cuirass in battle was during the Franco-Prussian War. The Imperial German and Russian cuirassiers subsequently discarded this armour for all but parade purposes but the twelve regiments of French heavy cavalry still in existence in 1914 wore their cuirasses on active service during the opening stages of World War I. Although some heavy cavalry regiments have remained into the 21st century, their large mounts are today used solely for ceremonial duties, such as those of the Household Cavalry in the United Kingdom.