HMS Princess Royal was a British battlecruiser built before World War I, the second ship of her class, which were nicknamed the "Splendid Cats". They were significant improvements over their predecessors of the Indefatigable class in terms of speed, armament and armour. This was in response to the first German battlecruisers, the Moltke-class, which were very much larger and more powerful than the first British battlecruisers, the Invincible-class.
She served in the Battle of Heligoland Bight a month after the war began and then was sent south to the Caribbean to prevent the German East Asia Squadron from using the Panama Canal. After the East Asia Squadron was sunk at the Battle of the Falkland Islands by the battlecruisers Invincible and Inflexible in December 1914 she rejoined the 1st Battlecruiser Squadron (BCS). During the Battle of Dogger Bank Princess Royal scored only a few hits, although one was the hit that crippled the German armoured cruiser Blücher so that she was caught and sunk by the concentrated fire of the British battlecruisers. Shortly afterwards Princess Royal became flagship of the 1st BCS, under the command of Rear Admiral Osmond Brock. She was moderately damaged during the Battle of Jutland and required a month and a half of repairs afterwards. She spent the rest of the war on uneventful patrols in the North Sea, although she did provide distant cover during the Second Battle of Heligoland Bight in 1917. Princess Royal was put into reserve in 1920 and sold for scrap in 1922 under the terms of the Washington Naval Treaty.