History of the Covenant

The Covenant, like almost all cultures, keeps a record of their history using their own methods of timekeeping. Unfortunately, the exact measures, if any, of these are a mystery, and there are hints that there may be multiple divisions of each age (9th Age of Reclamation, for example.) What is known is that the Covenant divide their recorded time into seven Ages, divided based on notable events within each. Each age is not necessarily a period of time, but a description of the events within it.

It is speculated that the Age of Reclamation is the last of the ages, when the Covenant fractures during their Civil War.

Age of Abandonment
The Covenant traces its history back at least 100,000 years, when an ancient species called the Forerunner activated the Halo installations, disappearing from the galaxy. This is referred to as the Age of Abandonment by the Covenant.

Age of Conflict
At some point before the Covenant’s formation, it's been recorded that the Sangheili and San 'Shyuum waged war against each other, apparently in a power struggle, in what is called the Age of Conflict. Additionally, the Grunt Rebellion took during the 39th Age of Conflict.

Ages of Discovery & Reconciliation
What is known is that the Prophets' discovery of ancient Forerunner artifacts during the Age of Discovery and the end of the war during the Age of Reconciliation, became the foundation on which the Covenant was founded upon. The Prophets promised to find the means of the Forerunners' transcendence and the Elites promised to protect the hierarchy. These ages marked the beginnings of the Covenant, the start of the Covenant’s search for Forerunner artifacts and presumably the Covenant Writ of Union.

The Covenant ship Truth and Reconciliation that appeared on Alpha Halo may have been named after this time period.

Age of Conversion
These were followed by the Age of Conversion, where the Covenant started their subjugation of other species in their search for Forerunner artifacts, incorporating them into their society, adding their strengths to their own. It is likely that the Taming of the Hunters occurred during this time period, requiring the creation of another Arbiter and defeated them only by threatening to destroy the homeworld of the Hunters. This period most likely included the incorporation of the Unggoy, Kig-Yar, Yanme’e and Huragok in separate Ages of Conversion.

Age of Doubt
The Age of Doubt is speculated to be a group of periods during which many of the Covenant began to lose faith in their mission. During the 29th Age of Doubt, the Grunt Rebellion occurred, instigated by the Jackals, requiring the creation of an Arbiter to quell. The last Age of Doubt, the 29th, ended in the year 2525, in human counting, leading into the Age of Reclamation.

Age of Reclamation
The Age of Reclamation was marked by the Human-Covenant War and the incorporation of the Jiralhanae into the Covenant's military. Originally, the war had been started by the Prophets of Truth, Mercy and Regret to prevent the majority of the Covenant learning that the humans were "descendants" of the Forerunners, their gods, and that the Covenant religion was based on a lie. As the decades wore on, tensions rose within the Covenant for a variety of reasons. Some Sangheili grew increasingly frustrated at apparent Prophet favoritism toward the Jiralhanae. Others began to question the validity of their holy crusade, beginning to see the humans as worthy adversaries rather than heretics. After the Changing of the Guard, where the Sangheili Honor Guards were replaced with Jiralhanae, these tensions erupted into full civil war in 2552 with the beginning of the Great Schism, where the Sangheili broke away from the Covenant, wresting away significant territories, personnel and equipment, allying themselves (at least grudgingly) with the humans they had formerly fought.

The Age of Reclamation also marked the discovery of a number of important Forerunner installations and outposts, ranging from minor artifacts uncovered on human colonies, to the massive installations of the Halo Array, such as the individual Halos, to two Shield Worlds, ending with the discovery and subsequent destruction of the Ark.

Known Timeline

 * 2200 B.C.E. - The San 'Shyuum Civil War begins
 * 2100 B.C.E. - The San 'Shyuum Civil War ends, Reformists flee the San 'Shyuum homeworld
 * 938 B.C.E. - The Sangheili are encountered by the San 'Shyuum, the Sangheili-San 'Shyuum War begins
 * 876 B.C.E. - The Sangheili reluctantly begin using Forerunner technology to improve their warships, arms and armor
 * 852 B.C.E. - The Sangheili-San 'Shyuum War comes to an end, and the Covenant is formed with the creation of the Writ of Union
 * 784 B.C.E. - Taming of the Lekgolo: the Lekgolo are discovered and incorporated into the Covenant
 * 648 B.C.E. - The San 'Shyuum homeworld is destroyed by a natural stellar collapse, and the Forerunner Dreadnought is made into the centerpiece of the new space station that will serve as the Covenant's capital, High Charity
 * 1112 - The Yanme'e are incorporated into the Covenant
 * 1342 - The Kig-Yar are discovered and form an alliance with the Covenant
 * 1552 - San'Shyuum begin searching for lifespan augmentation methods
 * 2142 - The Covenant incorporate the Unggoy into their society
 * 2462 - The Unggoy Rebellion occurs.
 * 2492 - The Jiralhanae are discovered and incorporated into the Covenant.
 * 2524 - First public appearance to humanity.
 * 2525 - The Covenant glass Harvest, declaring a genocidal campaign against the so-called "heretics".
 * 2552 - The Great Schism causes the Covenant to split up into two rival factions.
 * 2553 - The Human-Covenant War is officially declared over.

Trivia

 * The Covenant does not base their time on one age coming after another, they base the age on the state and being of the Covenant, entirely. For instance, the 9th Age of Doubt did not come before the 9th Age of Reclamation. It is instead the 29th Age of Doubt and then the 9th Age of Reclamation. Furthermore, each Age is broken up into Units and Cycles, the precise values of which are unclear.