The broadside ironclad ships, built mainly by Britain, France and Russia in the latter half of the nineteenth century, were a logical development of warship design after the long era of wooden warships with rows of cannon along their sides, before the advent of the turret or barbette mounted naval rifle.

These ships, of which the French La Gloire was the first example anywhere and HMS Warrior was the second, differed in concept from earlier line-of-battle ships only in that they carried armour plate, initially usually of some 4 to 5 inches in thickness, along their sides, rendering them effectively immune to the muzzle-loading ordnance, typically throwing a round-shot of between 18 and 42 pounds weight, carried in existing ships. The French Navys La Gloire (Glory) was the first ocean-going ironclad battleship in history. ... HMS Warrior (1860) (also known as Vernon III and Oil Fuel Hulk C77) was the worlds first ocean-going iron-hulled armoured battleship. ...

In contrast to the two- and three-decked wooden ships with which navies had been equipped for some three hundred years, these ships carried their armament upon the main deck only; the weight of their armour precluded any alternative. The size of the guns, however, increased rapidly as armoured ships became more resistant to incoming fire. The older guns rapidly gave way to 68-pounder smoothbore cannon, then to the unsuccessful Armstrong breech loaders, and then to larger muzzle-loading rifles.

A significant number of these ships were built, both in Britain and in France, in the 1860s, before battleship armament in turret or barbette became generally accepted from 1870. The advantages of mounting guns on both broadsides was that the ship could engage more than one adversary at a time, and the rigging did not impede the field of fire. The disadvantage was that multiple engagement was, in reality, an unlikely scenario, and that in single-ship combat or in a line-of-battle fleet action half the armament was out of action and was so much dead weight; whereas a ship mounting her armament in mid-line turrets could engage an enemy with all or most of her armament on both sides and over wide arcs of bearing. 1870 (MDCCCLXX) was a common year starting on Saturday (see link for calendar) of the Gregorian calendar or a common year starting on Monday of the 12-day-slower Julian calendar. ...

See List of battleships of the Royal Navy This is a list of battleships of the Royal Navy of England, Great Britain, and the United Kingdom. ...