2549

2549 was a year in the 2540s in the 26th century.

Before March

 * Before March 28: The Battle of Algolis occurs.

May

 * May 21: Dr. Catherine Halsey flash clones herself in order to create the seed brain for the AI Cortana, infringing the UN Colonial Mortal Dictata Act in the process.

August

 * August 26: At 22:43, a civilian engineer records "Log Entry 1" as part of Project Magnes, where she does test 1.0.
 * August 27: At 23:18, a civilian engineer records "Log Entry 4" as part of Project Magnes, where she does test 4.0.
 * August 29: At 10:37, a civilian engineer records "Log Entry 17" as part of Project Magnes, where she does conductive transfer test 17.

September
September 9
 * September 1: At 02:18, a civilian engineer records "Log Entry 39" as part of Project Magnes.
 * September 3: At 13:22, a civilian engineer records "Log Entry 44" as part of Project Magnes.
 * September 6: At 16:55, a civilian engineer records "Log Entry 57" as part of Project Magnes.
 * Fall of Arcadia. The Covenant glasses Arcadia.
 * At 15:43, a civilian engineer records "Log Entry 63" as part of Project Magnes.

September 10
 * At 12:18, a civilian engineer records "Log Entry 70" as part of Project Magnes, where she does test 70.
 * At 17:33, a civilian engineer records "Log Entry 72" as part of Project Magnes, where she does test 72.
 * September 12: At 23:43, a civilian engineer records "Log Entry 75" as part of Project Magnes.
 * September 14: At 13:38, a civilian engineer records "Log Entry 78" as part of Project Magnes, where she does test 78 and it succeeds.

October

 * October 16: The civilian log entries in regards to Project Magnes are compiled and entered into the UNSC Archives.

November

 * November 7: Cortana is created from one of Dr. Catherine Halsey's flash-cloned brains.

December

 * December 15: A mandatory psychiatric reevaluation for the members of NOBLE Team takes place. Jun-A266 is noted as having "an unhealthy emotional detachment in regards to the consequences of his actions".

Unknown

 * Paris IV is attacked. According to ONI documentation, Staff Sergeant Avery Johnson uses a box of plasma grenades to buy time for his Marines to evacuate, receiving a twelve-hundred-rad cumulative dose of radiation and later being diagnosed with Boren's Syndrome, which in the future will save his life from Flood infection on Installation 04 and onward. However, the Borens' Syndrome story involving Johnson is a hoax, a fabrication by ONI to cover his participation in the much earlier ORION Project.
 * The 2549 edition of the Hog is released either this year or late in 2548.
 * The Covenant recall their standard Type-26 Wraith model to update its design, fitting a Type-52 DESW on a ring mount.
 * Sometime during this year, the SPARTAN-II program is announced to the public, and any Spartan who dies is to be listed as either Missing In Action or Wounded in Action, to give the illusion that Spartans never die in accordance with the Office of Naval Intelligence Directive 930. Because the unidentified engineer took on Project Magnes with the hope that it could be used by John-117, it is likely that the SPARTAN-II program's public unveiling occoured prior to August 26.
 * Sometime prior to August 26, a civilian engineer submits schematics to the UNSC as part of Project Magnes, illustrating a concept for a device allowing for the rapid mass manipulation of heavy objects. The UNSC rejects the proposal, leading to the engineer deciding to build a prototype of the Grappleshot herself.