Timeline

Halo: Spartan Assault is a twin-stick shooter video game developed by 343 Industries and Vanguard Games. Part of the Halo franchise, the game was released on July 18, 2013, for Microsoft's Windows 8 and Windows Phone 8 platforms. The game was subsequently released on Xbox 360, Xbox One, Steam, and iOS. Halo: Spartan Assault is set between the events of Halo 3 and Halo 4. Players control the human soldiers Sarah Palmer and Edward Davis as they fight a new splinter faction of the alien Covenant. The game launched with 25 single-player missions; an additional campaign was released as downloadable content. The console versions also feature an exclusive cooperative horde mode.

Martin O'Donnell (born May 1, 1955) is an American composer, audio director, and sound designer best known for his work on video game developer Bungie's titles, including the Myth series, Oni, the Halo series, and Destiny. O'Donnell collaborated with Michael Salvatori for all of the scores; he has also directed voice talent and sound design for the Halo trilogy. O'Donnell began his career in music writing television and radio jingles such as the Flintstones Chewable Vitamins jingle and scoring for radio stations and films. O'Donnell moved to composing video game music when his company, TotalAudio, did the sound design for the 1997 title Riven.

Halo: Combat Evolved is a 2001 first-person shooter game developed by Bungie and published by Microsoft Game Studios. The game was released on November 15, 2001 for the Xbox, with ports to Microsoft Windows and Mac OS X released in 2003. It is the first installment in the Halo franchise. Set in the 26th century, players assume the role of Master Chief, a cybernetically enhanced supersoldier. Accompanied by an artificial intelligence construct named Cortana and the forces of the United Nations Space Command (UNSC), players battle against an alien theocracy known as the Covenant while they attempt to uncover the secrets of the eponymous Halo, a ring-shaped artificial world.

Halo 2 is a 2004 first-person shooter video game developed by Bungie and published by Microsoft Game Studios. Released for the Xbox in 2004, the game is the second installment in the Halo franchise and the sequel to 2001's Halo: Combat Evolved. In Halo 2's story mode, the player assumes the roles of the human supersoldier Master Chief and disgraced alien commander Arbiter in a 26th-century conflict between the United Nations Space Command, the genocidal Covenant, and later, the parasitic Flood.

Halo 3 is a 2007 first-person shooter video game developed by Bungie for the Xbox 360 console. The third installment in the Halo franchise following Halo: Combat Evolved (2001) and Halo 2 (2004), the game's story centers on the interstellar war between 26th-century humanity, a collection of alien races known as the Covenant, and the alien parasite known as the Flood. The player assumes the role of the Master Chief, a cybernetically enhanced supersoldier, as he battles the Covenant and the Flood. In cooperative play, other human players assume the role of allied alien soldiers. The game features vehicles, weapons, and gameplay elements familiar and new to the series, as well as the addition of saved gameplay films, file sharing, and the Forge map editor—a utility which allows the player to perform modifications to multiplayer levels.

Halo 3: ODST is a 2009 first-person shooter video game developed by Bungie and published by Microsoft Game Studios. The fifth installment in the Halo franchise, it was released on the Xbox 360 in September 2009. Players assume the roles of United Nations Space Command Marines, known as "Orbital Drop Shock Troopers" or ODSTs, during and after the events of Halo 2 and before the events of Halo 3. In the game's campaign mode, players explore the ruined city of New Mombasa to discover what happened to their missing teammates in the midst of an alien invasion. In the "Firefight" cooperative multiplayer option, players battle increasingly difficult waves of enemies to score points and survive as long as possible. The game also contains the entirety of Halo 3's multiplayer on a separate disc.

Halo Wars is a real-time strategy (RTS) video game developed by Ensemble Studios and published by Microsoft Game Studios for the Xbox 360 video game console. It was released in Australia on February 26, 2009; in Europe on February 27; and in North America on March 3. The game is set in the science fiction universe of the Halo series in the year 2531, 21 years before the events of Halo: Combat Evolved. The player leads human soldiers aboard the warship Spirit of Fire in an effort to stop an ancient fleet of ships from falling into the hands of the genocidal alien Covenant.

Halo: Reach is a 2010 first-person shooter video game developed by Bungie and published by Microsoft Game Studios for the Xbox 360 console. It is the sixth installment in the Halo series, and a direct prequel to Halo: Combat Evolved. The game takes place in the year 2552, where humanity is locked in a war with an alien theocracy known as the Covenant, which seeks to exterminate humanity. Players control Noble Six, a member of an elite squad of supersoldiers, known as Noble Team, attempting to stage a defense of the human world known as Reach, which falls under Covenant attack.

Halo 4 is a 2012 first-person shooter game developed by 343 Industries and published by Microsoft Studios for the Xbox 360. Halo 4's story follows a genetically enhanced human supersoldier, Master Chief, and his artificial intelligence construct Cortana, as they encounter unknown threats while exploring an ancient civilization's planet. The player assumes the role of Master Chief who battles against a new faction that splintered off from remnants of the Covenant, a former military alliance of alien races, as well as a new enemy: mechanical warriors of the Forerunner empire known as the Prometheans. The game features a new selection of weapons, enemies, and game modes not present in previous titles of the series.

Halo 5: Guardians is a 2015 first-person shooter game developed by 343 Industries and published by Microsoft Studios for the Xbox One. Set in the 26th century, the plot follows two fireteams of human supersoldiers: Blue Team, led by Master Chief, and Fireteam Osiris, led by Spartan Locke. When Blue Team goes absent without leave to track down the artificial intelligence construct Cortana, Master Chief's loyalty is called into question and Fireteam Osiris is sent to retrieve him. Players fight enemies with an armament of different weaponry and vehicles in story-based and multiplayer modes, including a larger-format 24-person mode called Warzone.

Halo Infinite is a 2021 first-person shooter video game developed by 343 Industries and published by Xbox Game Studios. It is the sixth mainline installment in the Halo series, following Halo 5: Guardians (2015). The game's campaign follows the human supersoldier Master Chief and his fight against a mercenary organization, known as the Banished, on the Forerunner ringworld Zeta Halo. Unlike previous mainline entries in the series, the multiplayer portion of the game is free-to-play.