The Roon class was a pair of armored cruisers built for the German Kaiserliche Marine (Imperial Navy) in the 1900s. The two ships of the class, Roon and Yorck, closely resembled the earlier Prinz Adalbert-class cruisers upon which they were based. The Roon class incorporated slight incremental improvements, including a pair of extra boilers. The ships were easily distinguished from their predecessors by the addition of a fourth funnel. Though the additional boilers were meant to increase the ships' speed, both vessels failed to reach their designed top speed. In addition, the ships had comparatively light armament and thin armor protection, so they compared poorly with their foreign contemporaries, particularly the armored cruisers of their primary opponent, the British Royal Navy.