The Irene class was a class of protected cruisers built by the Imperial German Navy (Kaiserliche Marine) in the late 1880s. The class comprised two ships, Irene and Prinzess Wilhelm; they were the first protected cruisers built by the German Navy. As built, the ships were armed with a main battery of fourteen 15 cm (5.9 in) guns and had a top speed of 18 knots (33 km/h; 21 mph). They were modernized in 1899–1905, and their armament was upgraded with new, quick-firing guns.

Both ships served in the East Asia station with the East Asia Squadron; Prinzess Wilhelm played a major role in the seizure of the Jiaozhou Bay Leased Territory in November 1897. Both ships returned to Germany at the turn of the 20th century, and remained in European waters until 1914, when they were removed from active service. They were reduced to secondary roles then, and continued to serve until the early 1920s, when they were sold for scrap.

In 1883, General Leo von Caprivi became the Chief of the Imperial Admiralty, and at the time, the pressing question that confronted all of the major navies was what type of cruiser to build to replace the obsolete rigged screw corvettes that had been built in the 1860s and 1870s. Cruisers could be optimized for service with the main fleet or for deployments abroad, and while the largest navies could afford to build dedicated ships of each type, Germany could not. The Reichstag (Imperial Diet) would not provide funding for such types. Furthermore, the navy had completed the cruiser construction program under the fleet plan of 1873 with the screw corvette Charlotte, which removed Caprivi's ability to use an approved fleet plan to justify further cruisers. The previous practice of building rigged corvettes for overseas use and avisos for fleet defense against small craft would no longer be tenable.

Despite the Reichstag's reluctance to fund new warships, many of the fleet's oldest cruising vessels were in need of replacement; the next scheduled to be replaced was the old screw frigate Elisabeth. Caprivi initially requested funding to replace the ship in 1883, which the Reichstag rejected. Caprivi, a general whose career had been spent in the Imperial German Army, created an Admiralty Council on 16 January 1884 to advise him, and the particulars of the next cruiser to be built was among the topics discussed. The council recommended a ship with the following characteristics: sufficient seaworthiness to permit operations in all sea and climate conditions; enough speed to catch or evade likely opponents; cruising radius necessary for long-range operations; and gun power strong enough to defeat expected opponents, but not to exceed 5 to 8% of the ship's displacement. The council discussed the matter over the course of several meetings in January, which Caprivi recorded in a memorandum dated 11 March. The document, which laid out Caprivi's thoughts on future naval construction in general, included requirements for 1st- and 2nd-class cruisers.

As work began on refining the proposals, the council set displacement at 3,500 t (3,400 long tons; 3,900 short tons) for the 1st-class variant, armament as a main battery of 15 cm (5.9 in) guns along with three torpedo tubes, speed was to be 17 knots (31 km/h; 20 mph), and the cruising radius must meet a minimum of 5,000 nautical miles (9,300 km; 5,800 mi). A 2nd-class version was also created on a displacement of 2,200 t (2,200 long tons; 2,400 short tons), with scaled down specifications in all other categories. The fleet's chief designer, Alfred Dietrich, set about turning these broad parameters into a proper design, but he quickly determined that no ship could be built to those specifications on the allotted displacement. He enlarged the 1st-class design significantly and increased displacement to 4,300 t (4,200 long tons; 4,700 short tons), and completed the design on 28 April 1885. Caprivi approved the plans on 1 May.

The historians Hans Hildebrand, Albert Röhr, and Hans-Otto Steinmetz remark that the new ships had "all the disadvantages of a compromise," and that they would not prove suitable as a fleet cruiser. Dirk Nottelmann concurred, noting that the ships "were neither well suited for fleet work nor for the increasing tasks in distant waters, like has been the case for most dual-purpose designs until today."

The ships were 98.90 m (324 ft 6 in) long at the waterline and 103.70 meters (340 ft 3 in) long overall. They had a beam of 14.20 m (46 ft 7 in) and a draft of 6.74 m (22 ft 1 in) forward. They displaced 4,271 metric tons (4,204 long tons) at designed displacement and 5,027 t (4,948 long tons) at full load. The hull was constructed with transverse and longitudinal steel frames, and the outer hull consisted of wood planking covered with Muntz copper sheathing to prevent fouling. The stem was made of bronze below the waterline and iron above. The hull was divided into ten watertight compartments and had a double bottom that extended for 49 percent of the length of the hull.

The ships were very good sea boats; they ran very well before the wind, and were very handy. They lost minimal speed in hard turns and suffered from moderate roll and pitch. In heavy seas, the ships were capable of only half speed, as both suffered from structural weakness in the forecastle. They had a transverse metacentric height of .69 to .72 m (2 ft 3 in to 2 ft 4 in). The ships had a crew of 28 officers and 337 enlisted men. The ships carried a number of smaller boats, including two picket boats, one pinnace, two cutters, one yawl, and two dinghies. Searchlight platforms were added to the foremast 13 m (42 ft 8 in) above the waterline.