HMS St Jean d'Acre was the Royal Navy's first 101 gun screw two-decker line-of-battle ship.

[2] Her construction used materials collected for a 90 gun Albion class sailing two-decker line-of-battle ship to be called St Jean d'Acre, which was ordered in 1844, but never laid down,[1] and suspended in 1845.

The Conqueror was designed as a slightly elongated St Jean d'Acre, and was laid down on the same slip at Devonport on 25 July 1853.

The cylinders were 70.75 in diameter, with a stroke of 3.5 ft.[2] On her Stokes Bay trials on 3 December 1853 the engine generated 2,136 ihp.

[1] In May 1854 she formed part of the Allied Fleet serving in the Baltic against Russia in the Crimean War.

Earl Granville was leader of the Liberal party in the House of Lords, and head of the British delegation to Alexander II's coronation.