The Lion-class cruiser was a class of guided missile cruisers that served with the UNSC Navy between 2619 and 2705. Entering service during a time of increasing galactic instability, numbers of ships planned and under construction swelled following the 2619 Strategic Defence Review, which orchestrated a wider escalation in the UNSC's military strength. The Lion-class played an ever-increasing role in the Galactic War (2622-2633) as it replaced older cruiser types, quickly proving its worth in combat against Jiralhanae, Unggoy and Kig-Yar forces. The UCG's victory in March 2633 was short lived however, and the Lion-class cruiser went on to serve throughout the Swarm War, until its conclusion in 2678. At its peak, the UNSC Navy operated over 6,900 cruisers of the Lion-class.