2523

March

 * March 11: Emile-239 is born on Luxor, Eridanus II.

July

 * July 14: SPARTAN-IIs train on Reach, where they successfully capture a Marine base flag.

Unknown

 * The SPARTAN-IIs are in their sixth year of training, they are now twelve years old.
 * At some point in the middle of the year, courtesy of increasing Insurrection activity, Jilian al-Cygni's workload begins to increase.
 * A rebellion breaks out on Andesia due to many citizens becoming extremely resentful of the Unified Earth Government and the planet's mega-corporate council that serves as Andesia's de facto planetary government.
 * April Orenski joins the Corbulo Academy of Military Science.