In 1878 Russia and Turkey were at war, and it was perceived by the British Government that Britain might be drawn into the conflict. This perception has become known to posterity as "the Russian war scare of 1878". In order to enhance the forces available to the Royal Navy, four ships were quickly purchased for a total cost of £2 million; Belleisle, Orion and from Turkey and from Brazil.
It would have been necessary in any case to detain the Turkish ships in British ports for the duration of hostilities to observe neutrality agreements, and in this situation compensation by purchase was essentially obligatory.
The ships were designed by a Turkish naval architect, Ahmed Pasha, as small ironclad rams of limited size and endurance for use in the eastern Mediterranean. They required considerable dockyard work after purchase to bring them up to anything near British standards in armament and equipment, but were never comparable in military value to other contemporary Royal Naval battleships. They were poorly armed and of low speed, and their meagre coal supply prevented their being used on blockade work or at any distance from a home port. They were, however, of shallow draught, allowing them to work close inshore, and after being labelled as "armoured rams" and "second-class battleships" they ultimately received their correct appellation as "coast-defence ships".