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Arbiter Thel 'Vadam and Fleet Admiral Hood shake hands in the Voi Memorial ceremony

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26th century

Years in the 2550s

For a complete list, see our timeline category.

2553 was a year in the 2550s in the 26th century. It was the first year that saw relative peace for humanity as the Covenant ceased to exist following its collapse during the Great Schism and its defeat at the end of the Human-Covenant War.[1] The end of the war was formalized with a ceremony in March 2553 with a prior treaty agreed upon between the Unified Earth Government and the Swords of Sanghelios in February 2553. Despite the end of large-scale hostilities and the absence of humanity being threatened with extinction, new factions sprung up in the power vacuum left behind by the ancient empire and new battles followed. 2553 was a year that saw the United Nations Space Command make major advances in terms of its technological prowess and military capability, despite a lesser reach over the galaxy incurred by the loss of so many colonies and assets during the decades of war. Ex-Covenant societies were faced with the challenge of redefining their purpose in a galaxy that no longer provided them with the rigid structure the hegemony had. Some sought revenge on humans and some on others from the Covenant. Some sought to be left alone and others made grabs for power. And some, such as Thel 'Vadam's Swords of Sanghelios, made in-roads with their former enemies for the mutual benefit of all parties.



January 1 After days of no indications that they were soon to be rescued following the destruction of Glyke and the UNSC Vacuna, Gray Team enters cryostasis.[2]

January 2553: Ilsa Zane announces her intention to steal the Infinity.

Before January 7

January 7

  • The first class of the SPARTAN-IV program, consisting of 145 volunteers, begin their augmentation procedures.[4]

January 8

January 15

January 26

January 27

January 27–31

January 31


February 2553: The survivors of the Onyx Conflict within the shield world

February 1

February 3

  • John-117 had a psychological monitoring scheduled for this date.[13]

February 1–15

February 15

  • Jun-A266 meets with Edward Buck on Sundown, where the latter had travelled with Veronica Dare for a vacation while on shore leave. Jun offers Buck the opportunity to join the SPARTAN-IV program. To Jun's surprise, Buck declines the offer, feeling that accepting would mean abandoning his team and Dare.[14][15]

February 18

  • It is three days to Margaret Paragoskys birthday, and Serin Osman gifts her a Huragok.[16]

February 19

  • 000 Tragic Solitude begins to research and catalog the myriad Flood forms and reflects on the uncomfortable truth the parasite exemplifies.[17]

February 21

  • Margaret Parangosky turns 92.[18]

February 28


Artwork for the Blooding Years
March 2553: The Servants of the Abiding Truth launch an attack on Kolaar Mountain.

March 1

March 2

  • John-117 had a interlace synchronization test scheduled for this date.[13]

March 3

March 16

March 22

  • The UNSC Infinity is launched after receiving its final upgrades with Forerunner technology.
  • Forces loyal to the Servants of the Abiding Truth launch an assault on Vadam, starting the Blooding Years.[24] This attack is eventually repelled by the arrival of the UNSC Infinity. During the battle, Jul 'Mdama's wife, Raia, is killed.
  • Admiral Parangosky approves the deployment of an automated probe delivery craft to Installation 00 using advanced slipspace technology.[25]


April 1

  • Jul 'Mdama escapes captivity on Trevelyan via a slipspace portal. He is transported to Hesduros, where he is welcomed by the local Sangheili as a messenger of the gods. Jul uses the locals' religious devotion to his own advantage and the result is the start of a new faction devoted to Covenant ideals.[26]

April 5

  • Kilo-Five returns to Venezia in order to track down the Kig-Yar pirate, Sav Fel, and the insurrectionist, Staffan Sentzke. Serin Osman is promoted to Rear Admiral and a small party is held aboard Port Stanley in her honor by Kilo-Five.

April 14

  • Sav Fel sells the Ket-pattern battlecruiser Pious Inquisitor to Staffan Sentzke, who intends to use the ship to force UEG authorities to provide answers about the disappearance of his daughter many years earlier. Fel demonstrates the ship's capabilities by using its energy projector to glass Forerunner ruins on Shaps III.[27] This causes Line Installation 444-447 to send an automated distress signal to Covert Support Base 4276, located on planet Gao in the nearby Cordoba system. The distress call awakens the support base's archeon-class ancilla, Intrepid Eye, from stasis. After her requests for a status report, Intrepid Eye attempts to launch a reconnaissance drone, triggering a cave-in which cripples Support Base 4276 almost entirely.[28]
  • Vasily Beloi and Malcolm Geffen infiltrate the Venezian militia in order to gather information about Sentzke and Pious Inquisitor. Following a series of suspicious incidents, Sentzke begins to doubt their cover story and has them detained and tortured. Naomi-010 and Lian Devereaux eventually arrive and successfully extract Mal and Vaz. During the rescue, Sentzke is also taken captive aboard Port Stanley.
  • A Kig-Yar crew led by Shipmistress Chol Von tracks down and boards Pious Inquisitor with the intent of seizing the ship for itself. Kilo-Five boards Pious Inquisitor and a skirmish occurs between it and the Kig-Yar. Chol Von eventually has her crew destroy the ship. Staffan Sentzke is presumed dead in the ensuing explosion, but he actually had managed to escape.
  • Several tourists exploring Gao's Montero Cave System find themselves miraculously cured of various illnesses and the caves quickly see an influx of sick people hoping for similar miracle cures.[29] The cures are actually the work of the Lifeworker Huragok Roams Alone, attached to Gao's Support Base 4276.[28]
  • Commander Murtag Nelson, a field analyst at an ONI listening post, takes note of strange transmissions emanating from the Montero Cave System on Gao. Nelson correctly hypothesizes that a Forerunner ancilla is responding to the bombardment on Shaps III. Admiral Parangosky subsequently gives Nelson command of the 717th Xeno-Materials Exploitation Battalion and tasks them with retrieving the Forerunner AI.[27]



May 6

  • ONI learns the Banished had raided an air base formerly belonging to the Covenant, and that its leader, Atriox, had been captured and taken aboard the assault carrier Enduring Conviction. Twelve hours later, the Enduring Conviction broke formation and contact with the rest of its fleet. The Conviction was hailed, warned, and then fired upon when it ignored orders. The ship performed evasive maneuvers, returned fire and escaped. Shortly after this, the ship and its crew, led by Let 'Volir, swore fealty to the Banished.[32]

May 7

  • The research and development vessel Argent Moon is commissioned by ONI.[33]

May 14 (approximately)

  • A UNSC task force enters the Cordoba system and requests permission to conduct research in Gao's Montero Cave System. While Gao's planetary government initially denies the requests, President Aponte eventually allows a small research team to land. The UNSC subsequently deploys the 717th Xeno-Materials Exploitation Battalion, along with the attached Blue Team, to the Montero region and declares the caverns off-limits to anyone else.[29]
  • After the UNSC battalion's arrival, several people are found brutally murdered in the Montero Cave System. The murders are the work of the Forerunner ancilla Intrepid Eye, who seeks to generate conflict among the humans in order to force the UNSC to cease its efforts to capture her.[28]




July 4–5, 2553: The Battle of Wendosa.

July 2

July 3

  • Members of Blue Team accompany Lopis and her partner, Cirilo in a search for the missing Halal and Hayes. They arrive at their location and discover their corpses. Fred recovers the fragment of Wendell from Halal's damaged TACPAD and places him in his helmet's data chip. While investigating the scene, Cirilo finds a trail of blood from Roams Alone and the team resolves to follow it.

July 4

  • Intrepid Eye directs Aggressor Sentinels to attack the humans and though they destroy the Sentinels, Cirilo is killed and Olivia-G291's legs are badly wounded. Veta Lopis learns of Gamma Company's unique augmentations and places them, Mark-G313 in particular, at the top of her list of suspects for the murders. The humans are met by Roams Alone, who they agree to take with them back to the surface. The Keepers launch an attack on Wendosa, believing that Intrepid Eye is in the town. The group also dispatches forces into the caverns which come into conflict with Veta and the Spartans.

July 5

  • Fred-104 captures Intrepid Eye with a scramble grenade. The ancilla escapes and is pursued by the UNSC and Keepers alike and is eventually recaptured by he, Olivia, and Ash. Fred boards a UH-144 Falcon with the ancilla but is shot down. Veta Lopis attacks Castor and wounds him before the Jiralhanae can harm Fred. The 717th Xeno-Materials Exploitation Battalion's Alpha Company arrives at their location to fend off the Keepers.

July 6




The Prelate and the Scion.
September 2553: Tem'Bhetek engages Rtas 'Vadum and Tul 'Juran aboard the Shadow of Intent.



October 14


November 23

November 28

  • Luther Mann, while exploring Trevelyan, discovers the location of Installation 07.[41]
  • A pioneer group arrives at Reach to prepare for the planet's eventual reterraforming.[42]
  • The ONI probe delivery drone dispatched in March arrives at Installation 00 and deploys its probes. After initial transmissions confirm the Ark's survival, all of the probes go offline.[25]


December 6

December 8

  • The Office of Naval Intelligence sends Veta Lopis' Ferret Team to find her killer and rescue her family.

December 12

December 21

  • Two ONI agents, 'D' and 'S', speculate which are Atriox's motivations after the demise of the Covenant empire.[44]
  • The UNSC commissions the UNSC Rubicon, a ship equipped with state-of-the-art Forerunner slipspace drive technology, remote contact teams and survey drones, for a manned mission to the Ark.[25]
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Unknown date[edit]


  1. ^ Halo Wars 2 GAMEPLAY - E3 2016 Interview (Interview with Kevin Grace) - "The Covenant are dead"
  2. ^ Halo: Envoy, Chapter 12
  3. ^ Halo: Initiation, Issue #1
  4. ^ Halo Waypoint - Spartans
  5. ^ Halo Waypoint: Catalog Interaction (Query Answer: Human records indicate transition to noncombatant administrative control [ref: UEG] [January 8, 2553]. No notable adjustment in military [bureaucratic tactical] behavior and scope of authority.)
  6. ^ Halo Waypoint - Halo: Glasslands excerpt, Chapter 2
  7. ^ Jessica Shea Twitter Today in Halo - 1/8/2553
  8. ^ Halo Legendary Crate, Data Drop #8
  9. ^ Halo: Glasslands, page 79
  10. ^ a b Halo: Initiation, Issue #3
  11. ^ Halo: Evolutions - Essential Tales of the Halo Universe, From the Office of Dr. William Arthur Iqbal
  12. ^ Jessica Shea Twitter Today in Halo - 2/1/2553
  13. ^ a b Youtube, Halo: The Master Chief Collection - Wake Up, John
  14. ^ Halo: New Blood, pages 49-55 (Google Play edition)
  15. ^ Twitter: Today in Halo 2/15/2553
  16. ^ Halo: Glasslands, chapter 10
  17. ^ Halo Wars 2, Phoenix Logs — An Uncomfortable Truth Part 1
  18. ^ Halo: Glasslands, chapter 13
  19. ^ Halo Waypoint: Catalog Interaction - Page 14
  20. ^ Halo Legendary Crate, Data Drop #2
  21. ^ Halo 3, campaign level Halo
  22. ^ Jessica Shea's Twitter - Today in Halo: 3/16/2553
  23. ^ Halo: The Thursday War, pages 22-23
  24. ^ Halo: The Thursday War, page 28
  25. ^ a b c Halo: Hunters in the Dark, Chapter 2
  26. ^ Twitter: Today in Halo 4/1/2553
  27. ^ a b Halo: Last Light, pages 22-23 (Google Play edition)
  28. ^ a b c Halo: Last Light, pages 36-39 (Google Play edition)
  29. ^ a b Halo: Last Light, pages 8-10 (Google Play edition)
  30. ^ Halo Mythos, page 128
  31. ^ Halo 4: The Essential Visual Guide
  32. ^ Halo Wars 2, Phoenix Logs — Rise of Atriox III
  33. ^ Halo Waypoint: Argent Moon
  34. ^ Halo: Last Light, pages 5-6 (Google Play edition)
  35. ^ Halo: Last Light, Chapter 28
  36. ^ a b Halo: Last Light, Chapter 28, pages 330-331 (Google Play edition)
  37. ^ a b Halo Waypoint: Catalog Interaction - Page 38
  38. ^ Halo: Shadow of Intent, pages 79-80 (Google Play edition)
  39. ^ Halo: Fractures, "A Necessary Truth"
  40. ^ Halo: Retribution, chapter 4
  41. ^, Today in Halo
  42. ^ Halo Waypoint - Catalog Interaction (Page 43)
  43. ^ Halo: Retribution Chapter 1
  44. ^ Halo Wars 2 - Phoenix Logs: Rise of Atriox IV
  45. ^ Halo Encyclopedia (2022 edition), page 121
  46. ^ Halo: Escalation - Issue #7
  47. ^ Halo: Reach Legendary Edition - Noble team Statue Instructions
  48. ^ Halo: Escalation - Issue #17
  49. ^ Halo Mythos, p. 132
  50. ^ Halo 4: The Essential Visual Guide - Page 152
  51. ^ Halo: Bad Blood
  52. ^ Halo: Official Spartan Field Manual, page 202
  53. ^ Halo: Official Spartan Field Manual, page 204
  54. ^ Halo Waypoint: Canon Fodder - Tales & Stingers
  55. ^ Halo Encyclopedia (2022 edition), page 462