SMS Hessen was the third of five pre-dreadnought battleships of the Braunschweig class. She was laid down in 1902, was launched in September 1903, and was commissioned into the German Kaiserliche Marine (Imperial Navy) in September 1905. Named after the state of Hesse, the ship was armed with a battery of four 28 cm (11 in) guns and had a top speed of 18 knots (33 km/h; 21 mph). Like all other pre-dreadnoughts built at the turn of the century, Hessen was quickly made obsolete by the launching of the revolutionary HMS Dreadnought in 1906; as a result, she saw only limited service with the German fleet.
Hessen's peacetime career centered on squadron and fleet exercises and training cruises. She was involved in two accidental collisions, with a Danish steamship in 1911 and a German torpedo boat in 1913. Hessen was slated to be withdrawn from service in August 1914, but the start of World War I in July interrupted that plan and she remained in service with the High Seas Fleet. She performed a variety of roles in the first two years, serving as a guard ship at the mouth of the Elbe, patrolling the Danish straits, and supporting attacks on the British coast, including the raid on Scarborough, Hartlepool and Whitby in December 1914 and the Bombardment of Yarmouth and Lowestoft in April 1916. The following month, Hessen was present at the Battle of Jutland, the largest naval battle of the war. In the last daytime action between capital ships on 31 May, Hessen and the other pre-dreadnoughts of II Battle Squadron covered the retreat of the battered German battlecruisers away from the British battlecruiser squadron.
Jutland revealed how inadequate pre-dreadnoughts like Hessen were in the face of more modern weapons, so she and the rest of II Squadron ships were withdrawn from service with the fleet. She was decommissioned in December 1916, disarmed and used as a depot ship for the rest of the war. Hessen was one of the few obsolete battleships Germany was permitted to retain under the terms of the Treaty of Versailles. Rearmed, she served with the fleet in the 1920s and early 1930s, though she was withdrawn from front-line service in 1934. The following year, Hessen was converted into a radio-controlled target ship. She served in this capacity through World War II, also working as an icebreaker in the Baltic and North Seas. The ship was ceded to the Soviet Union in 1946 after the war, renamed Tsel, and served until she was scrapped in 1960.