HMS Indomitable was one of three Invincible-class battlecruisers built for the Royal Navy before World War I and had an active career during the war. She tried to hunt down the German ships Goeben and Breslau in the Mediterranean when war broke out and bombarded Turkish fortifications protecting the Dardanelles even before the British declared war on Turkey. She helped to sink the German armoured cruiser Blücher during the Battle of Dogger Bank in 1915 and towed the damaged British battlecruiser HMS Lion to safety after the battle. She damaged the German battlecruisers Seydlitz and Derfflinger during the Battle of Jutland in mid-1916 and watched her sister ship HMS Invincible explode. Deemed obsolete after the war, she was sold for scrap in 1921.

The three Invincible-class battlecruisers were built for the Royal Navy and entered service in 1908 as the world's first battlecruisers. They were the brainchild of Admiral Sir John ("Jacky") Fisher, the man who had sponsored the construction of the world's first "all-big-gun" warship, HMS Dreadnought. He visualised a new breed of warship, somewhere between the armoured cruiser and battleship; it would have the armament of the latter, but the high speed of the former. This combination would allow it to chase down most ships, while allowing it to run from more powerful designs.