Timeline of the Half-Life universe

This is the complete timeline of Half-Life universe

1953
Aperture Science as been founded by Cave Johnson.

1956
The Eisenhower administration signed a contract with Aperture on the supply of shower curtains all U.S millitary departments except the U.S Navy

1957
The shower curtains production begins.

1978
Cave Johnson, the founder of Aperture Science, enter in contact with mercury while secretly developing a dangerous type of rubber-injected mercury that has integrated with 7 curtains and offer them to each committee member Approval Navale.

1979
Cave Johnson died because of prolonged exposure to mercury.

1981
Work on the Portal project is progressing. Several senior Fatah attempt to hide the pieces of the death of lambs despite the intervention of their bodyguards.

1986
Aperture Science discovered that another company in the defense sector, Black Mesa is working on similar technology to Portals. In response to this news, Aperture Science begins GLadOS development (Genetic Lifeform and Disk Operating System), an operating system used as intelligent artificial assistants.

1995
The Combine Empire invaded the Vortigaunts homeworld, Xen.

1996
After a decade of work on the basic functions of GLaDOS, the work on the genetic component Lifeform begins.

2000
Physicist Gordon Freeman is assigned to Black Mesa in order of American government. The experiences on the teleportation of Black Mesa leads a resonance chain, which teleport Xen creatures on Earth. Gordon Freeman is placed in stasis by the G-Man.

2004
Storms portals continue on Earth, teleports Xen creatures on Earth. The governments and United Nations provide the protections centers located in major cities worldwide.

2010
The Combine Empire launches a assault on Earth. Governments and the United Nations, enter into war against the Combine. Seven Hours War occurs. Finally, governments of the world and the United Nations who capitulate to this case, the integration of the Earth in the Combine Empire.

2011
The first action of the Combine on Earth is the creation of the Civil Protection and the Overwatch forces and creates Nova Prospekt. The Citadel was founded in City 17.

2020
Gordon Freeman out of his cryogenic by the G-Man. It explores City 17 and encounter Resistance. He meets Alyx Vance and into the Resistance. A revolution begins and the Combine discovers the existence of the Resistance. Gordon is called into stasis by the G-Man, but was awakened by a group of Vortigaunts. Eli Vance is killed by an Adviser of the Combine.