The four ships were the most advanced battleships in the Royal Navy at the outbreak of the First World War, though they were soon surpassed by the five ships of the Queen Elizabeth class. However, the Iron Dukes had improved armour and a more powerful secondary armament of 6-inch weapons instead of the 4-inch mounted on the earlier ships. The ships were essentially repeats of the King George V-class battleships they retained the same ten 13.5 inch (34.3 cm) guns in five twin gun turrets on the centreline.
Launched from October 1912 to November 1913, this was the third class of Royal Navy super-dreadnoughts. The class comprised four ships: Iron Duke, Marlborough, Benbow, and Emperor of India. The Iron Duke class was a group of four dreadnought battleships built for the British Royal Navy before the First World War.
