The first game in the Halo series was released, marking the beginning of one of the most popular franchises in gaming.
The highly anticipated sequel to Halo: Combat Evolved was launched, featuring multiplayer capabilities that became a significant part of its success.
The third installment of the main Halo series was released on Xbox 360 and became a major hit, concluding the original trilogy.
A prequel to the original Halo trilogy, Halo: Reach was launched, further expanding the series' lore and gameplay.
The first Halo game developed by 343 Industries, marking a new chapter for the franchise after Bungie's departure.
The latest mainline entry released on Xbox One, continuing the story of Master Chief and introducing new gameplay features.
The newest main canonical entry in the series was released, featuring new graphics engine and continuing Master Chief's story.
The Covenant, a religious alliance of alien species, begins its war against humanity after discovering humans interfered with their sacred Forerunner artifacts.
Dr. Catherine Halsey starts the SPARTAN-II program to create super-soldiers to combat human insurrectionists but later become crucial in fighting the Covenant.
Covenant forces launch a devastating attack on the human colony of Reach, resulting in its fall and the near destruction of the UNSC's military assets.
UNSC discovers a mysterious ringworld called Installation 04, later revealed to be a superweapon created by the Forerunners.
Master Chief John-117 battles the Covenant and the Flood on Installation 04 to prevent the activation of the Halo ring, which would destroy all sentient life.
Master Chief activates Installation 04, destroying it to prevent the Covenant from using it, while escaping aboard the Pillar of Autumn.
Covenant invades Earth leading to a major conflict wherein Master Chief discovers another Halo ring, Installation 05 (Delta Halo).
Master Chief fights both the Covenant and the Flood on Installation 05 and stops the ring's activation to save sentient life.
The ongoing conflict between humanity and the Covenant escalates with new threats arising including the Flood and Prometheans.
