Russian cruiser Rurik (1906) in the context of "Armored cruiser"

The armored cruiser was a type of warship of the late 19th and early 20th centuries. It was designed like other types of cruisers to operate as a long-range, independent warship, capable of defeating any ship apart from a pre-dreadnought battleship and fast enough to outrun any battleship it encountered.

For many decades, naval technology had not advanced far enough for designers to produce a cruiser that combined an armored belt with the long-range and high speed required to fulfill its mission. For this reason, beginning in the 1880s and 1890s, many navies preferred to build protected cruisers, which only relied on a lightly armored deck to protect the vital parts of the ship. However, by the late 1880s, the development of modern rapid-fire breech-loading cannons and high-explosive shells made the reintroduction of side armor a necessity. The invention of case-hardened armor in the mid-1890s offered effective protection with less weight than previously.