SMS Hagen was the final vessel of the six-member Siegfried class of coastal defense ships built for the German Imperial Navy. Her sister ships were Siegfried, Beowulf, Frithjof, Heimdall, and Hildebrand. Hagen was built by the Kaiserliche Werft in Kiel between 1891 and 1893, and was armed with a main battery of three 24-centimeter (9.4 in) guns. She served in the German fleet throughout the 1890s and was rebuilt in 1900 - 1902. She served in the VI Battle Squadron after the outbreak of World War I in August 1914, but saw no action. Hagen was demobilized in 1915 and used as a barracks ship thereafter. She was ultimately sold for scrap in 1919 and subsequently dismantled.

The Siegfried class was a group of six coastal defense ships built by the German Kaiserliche Marine in the late 19th century. The ships were intended to protect the German coastline from naval attacks. The class comprised the lead ship Siegfried, along with her sisters Beowulf, Frithjof, Heimdall, Hildebrand, and Hagen. All six ships were named after Norse mythological figures. Two further vessels, the Odin class, were built to a similar design but were not identical.