The Conqueror-class ships of the line consisted of a pair of 101-gun second rate screw-propelled ships designed by the Surveyor's Department for the Royal Navy.
The Conqueror class ships were designed in 1852 as two-decker 101-gun second rates in a period when many under-construction sailing ships of the line were being redesigned to use screw propulsion in addition to sail. Two ships were subsequently completed, and .
Both ships saw service in the Channel Squadron, and later in the Crimean War. Both were used to transport troops to Mexico in support of the French intervention there in 1861. HMS Conqueror was wrecked on Rum Cay whilst carrying this out, but without losses, and most of her machinery, guns and stores were subsequently salvaged. The advent of armoured ironclads, such as in the 1860s made the traditional ships of the line largely obsolete. HMS Donegal continued in service as a guard ship, in which role she took the last surrender of the American Civil War. She was hulked in 1886, and became part of the torpedo training school . She served until the establishment moved on shore in 1923, and was broken up in 1925.