SMS Derfflinger was a battlecruiser of the German Kaiserliche Marine built just before the outbreak of World War I. She was the lead vessel of her class of three ships; her sister ships were Lützow and Hindenburg. The Derfflinger-class battlecruisers were larger and featured significant improvements over the previous German battlecruisers, in terms of armament, armor protection, and cruising range. The ship was named after Field Marshal Georg von Derfflinger who fought in the Thirty Years' War.