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 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. 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.

Pre-dreadnought battleships were sea-going battleships built from the mid- to late- 1880s to the early 1900s. Their designs were conceived before the appearance of HMS Dreadnought in 1906 and their classification as "pre-dreadnought" is retrospectively applied. In their day, they were simply known as "battleships" or else more rank-specific terms such as "first-class battleship" and so forth. The pre-dreadnought battleships were the pre-eminent warships of their time and replaced the ironclad battleships of the 1870s and 1880s.