The ships were ordered in an effort to strengthen the defensive capabilities of the Austro-Hungarian Navy, during a period where funding for more expensive ironclad warships could not be secured from parliament.

These included active duty with the main fleet in home waters, overseas training cruises, and showing the flag abroad.

During World War I, the cruisers were mobilized for coastal defense duties, but saw no major action, apart from Panther shelling Montenegrin forces in 1916.

The Austro-Hungarian Marinekommandant (Navy Commander), Vizeadmiral (Vice Admiral) Maximilian Daublebsky von Sterneck, argued in a memorandum of 8 September 1884 addressed to Kaiser Franz Joseph I the fleet was too weak and must be expanded.

He acknowledged that the government had failed to meet the fleet plan that had been outlined by VAdm Wilhelm von Tegetthoff in the early 1870s, owing to the chronically short naval budgets approved by the Imperial Council of Austria and the Diet of Hungary.

Since new, more powerful, and thus more expensive ironclads could not be built, Sterneck made the argument that cheaper defensive weapons should be acquired; these included naval mines and more effective torpedo-armed ships.

The Austro-Hungarian Navy established a commission to examine the designs submitted by the British firms; Armstrong received the contract in part because they could build the ships more cheaply.

While the vessels were under construction, Popper discovered that the designers had made a serious error distributing the weight of the ships, such that the difference between the forward and aft draft was 1.5 m (4 ft 11 in).

In fact, Panther and Leopard provided the basis for the follow-on design, SMS Tiger, which was a slightly enlarged version of the earlier ships.

During the speed trials, Armstrong experimented with using smaller screws with lower pitch in an attempt to exceed 19 knots (35 km/h; 22 mph), but the tests proved unsuccessful.

[7][8] Unlike earlier cruising ships of the Austro-Hungarian Navy, Panther and Lussin did not carry a sailing rig to supplement their steam engines.

[7][8] After their crews arrived to take them back to Austria-Hungary in early 1886, both vessels were taken into the navy's shipyard in Pola, where their armament was installed over the course of 1887, to include their torpedo tubes.

The two cruisers spent much of the early 1890s laid up, with Panther being reactivated in 1896 for a major training cruise in the Pacific Ocean from May 1896 to February 1898, and Leopard returning to service in 1897 to participate in an international naval demonstration off the island of Crete during the Greco-Turkish War.

[13][14][15] After Austria-Hungary's defeat in November 1918, both ships were ceded as war prizes to the victorious Allies, and Britain received both vessels under the terms of the Treaty of Saint-Germain-en-Laye.