The Korolev-class cruiser was a type of starship on active duty in Starfleet during the early 23rd century. (Starfleet Prototypes) The Korolevs were in service from ca. 2225 to at least the 2240s. Of the class, the only known name was the lead ship and prototype, USS Korolev The Korolev class is said to be the precursor class to the Constitution-class. This may be true only in the continuity of Strategic Design.