Battle of Leonis Minoris

The Battle of Leonis Minoris was a battle of the Human-Covenant War. In 2537, the Covenant discovered the human presence in the Leonis Minoris System, and proceeded to wipe out the colonists there. The UNSC rushed to the system's defense with a large force of starships, but the battle ended in disaster as ten ships were lost in battle against the technologically-superior Covenant. After the brief engagement, the UNSC was forced to abandon the system, and the Covenant proceeded to destroy the system.

Aftermath
Although the UNSC Navy considered the loss of ten vessels to be relatively minor, the Covenant succeeded in eradicating both of the UNSC Colonies in the system.