SMS Schleswig-Holstein in the context of "Germaniawerft"

Westerplatte (Polish pronunciation: [vɛstɛrˈplatɛ], [ˈvɛstɛrplatɛ], German pronunciation: [ˈvɛstɐplatə]) is a peninsula in Gdańsk, Poland, located on the Baltic Sea coast mouth of the Dead Vistula (one of the Vistula delta estuaries), in the Gdańsk harbour channel. From 1926 to 1939, it was the location of a Polish Military Transit Depot (WST), sanctioned within the territory of the Free City of Danzig (now Gdańsk).

The first shots of the Second World War were fired at the Battle of Westerplatte which began at 0450hrs on the 1 September, 1939. The fighting started when the German WWI battleship SMS Schleswig-Holstein began shelling the Polish ammunition depot on Westerplatte. After a siege that lasted a week, the Polish garrison surrender to German forces that were part of invasion of Poland.

The Deutschland class was a group of five pre-dreadnought battleships built for the German Kaiserliche Marine (Imperial Navy), the last vessels of that type to be built in Germany. The class comprised Deutschland, the lead ship, Hannover, Pommern, Schlesien, and Schleswig-Holstein. The ships closely resembled those of the preceding Braunschweig class, but with stronger armor and a rearranged secondary battery. Built between 1903 and 1908, they were completed after the launch of the revolutionary British all-big-gun battleship HMS Dreadnought in 1906. As a result, they were obsolescent before entering service. The ships nevertheless saw extensive service in the High Seas Fleet, Germany's primary naval formation, through the late 1900s and early 1910s, when they were used for training, which included overseas cruises.

Following the start of World War I in July 1914, the German fleet adopted a strategy of raids on the British coast, which the five Deutschland-class ships supported. These operations culminated in the Battle of Jutland on 31 May – 1 June 1916, where all five ships saw action, despite their marked inferiority to British dreadnoughts. Regardless, they intervened to protect the battered German battlecruisers from their British counterparts, allowing them to escape. In the confused night actions, Pommern was torpedoed and sunk by a British destroyer. After the battle, the four surviving ships were removed from front-line service and used for coastal defense through mid-1917. Thereafter, Hannover alone remained on patrol duty, while the rest were used as barracks or training ships. After Germany's defeat, the Treaty of Versailles permitted the postwar navy to retain several old battleships for coastal defense, including the four Deutschland-class ships.