After completing a series of sea trials and training exercises, the ship was pronounced ready for service with the fleet on 5 April She was armed with a main battery of eight mm 8 in guns and, although nominally under the 10,long-ton 10, t limit set by the Anglo-German Naval Agreement , actually displaced over 16, long tons 16, t.
The ship led the flotilla of warships into the Oslofjord on the night of 8 April, to seize Oslo , the capital of Norway. Two old 28 cm 11 in coastal guns in the Oscarsborg Fortress engaged the ship at very close range, scoring two hits, as did several smaller guns in other batteries. Two torpedoes fired by a torpedo battery in the fortress struck the ship, causing serious damage. The fire spread to one of her anti-aircraft gun magazines, causing a large explosion, and then spread further to the ship's fuel bunkers.
The wreck lies at the bottom of Oslofjord, and in was designated as a war memorial to protect it from looters. Several artifacts have been raised from the wreck, including one of her Arado floatplanes , which was recovered during an operation to pump out leaking fuel oil from the ship in The Admiral Hipper class of heavy cruisers was ordered in the context of German naval rearmament after the Nazi Party came to power in and repudiated the disarmament clauses of the Treaty of Versailles.
In , Germany signed the Anglo—German Naval Agreement with Great Britain, which provided a legal basis for German naval rearmament; the treaty specified that Germany would be able to build five 10, long-ton 10, t " treaty cruisers ". The turbines were supplied with steam by twelve ultra-high pressure oil-fired boilers. She had four triple The main battery turrets had mm 4. By the end of the month, the ship was ready for sea trials ; she steamed to Gotenhafen in the Baltic Sea.
In January , she resumed her exercises in the Baltic, but by the middle of the month, severe ice forced the ship to remain in port. On 5 April, she was deemed to be ready for action, and was therefore assigned to the forces participating in the invasion of Norway.
