• 1918 - American scientists discover the presence of the mutant gene within some individuals. This information is classified. Research into the gene begins, eventually becoming Project: Rebirth over the decades.

• 1941 - Dr. Berthold Sternberg reaches a breakthrough resulting in the Infinity Formula. This formula is administered to an elite Army Rangers unit, led by Sgt. Nick Fury and Cpl. Timothy "Dum Dum" Dugan. Dubbed the Howling Commandos, these Army Rangers were the first known super soldiers.

• 1942 - German defector Dr. Abraham Erskine completes his own research into Project: Rebirth resulting in the Super-Soldier Serum, a more completed formula, before his subsequent murder. Steve Rogers becomes the first test subject for the serum and joins the war efforts as Captain America.

• 1945 - Captain America is declared KIA.

• 1947 - The Roswell incident is humanity's first known interaction with extraterrestrial life in modern history as a Kree drone crashlands and self-destructs in the desert. Almost none of the wreck is salvageable.

• 1949 - The Strategic Homeland Intelligence, Enforcement and Logistics Division is founded in the early years of the Cold War. Col. Nick Fury is given command of the spy agency.

• 1950s - Attempts to replicate the successes of Project: Rebirth by the CIA and American military lead to the forcible recruitment of 300 black soldiers as test subjects.

• 1962 - A whistleblower outed Project: Rebirth's increasingly immoral and illegal experimentations resulting in 10 months of Congressional inquiries and the termination of the program.

• 1963 - The knowledge of the mutant gene is released to the general public. This leads to hysteria and civil unrest that spans years.

• 1973 - Project MK-Ultra ends its illegal human testing. In its stead, John Sublime begins his illegal mutant experimentations as a new clandestine program; Weapon: Plus.

• 1980s - Renewed efforts for mutant civil rights lead to mass protests. The Brotherhood of Mutants forms, initially as a political activist group, and quickly transitions into a violent revolutionary group preaching about mutant power and superiority. Likewise, the Purifiers, a violent anti-mutant hate group begins committing acts of domestic terrorism against mutant civilians. The conflict between the two lasts the whole decade until both organizations' leaderships are arrested by the FBI and disbanded.

• 1989 - SHIELD is mothballed as President Reagan's final act in office.

• 2010 - Sixteen cities across the Earth are assaulted by an alien invasionary force. The Chitauri, led by their queen, cause widespread, unprecedented damage and terror in a war lasting 44 hours. This incursion is ended largely due to the efforts of mutants across the world, and a ragtag strike team of enhanced individuals attacking the queen's mothership over the United Nations building in New York City.
  
  • The acts of mutants in defense of the planet cause a massive decrease in anti-mutant sentiments and an increase in public approval ratings for pro-mutant politicians.
  • The individuals responsible for assaulting the alien mothership and defeating the Chitauri queen are recruited by the National Security Council to a new initiative meant to defend America against future attacks. These individuals become publicly known as Earth's Avengers.
  • SHIELD is resurrected to be a proactive bastion against possible threats, absorbing the Department of Homeland Security, with Dum Dum Dugan appointed director.
  • The Sentinel Program is created, led by Bolivar Trask, to create new weapons of mass destruction capable of fending off planetary invasions.
  • A superhuman arms race is heralded by private corporations and industrialists in a bid to create and sell the next super soldier. Norman Osborn declares his corporation will be the first to design a new, stable super serum.
  • Vigilantism by enhanced individuals becomes commonplace. This soon develops into the first known acts of superheroism.

• 2012 - The first helicarrier, the Triskellion, is constructed and becomes SHIELD's flagship and mobile headquarters.

2018 - Mutant terrorist Franklin Hall, AKA Gravitron, becomes the Avengers' first genuine enhanced threat.

• Anti-mutant sentiments rearise as conspiracy theories, courtesy of radicals like the Friends of Humanity, begin to spread across the internet.
• Graydon Creed, a known member of the Friends of Humanity, is elected to Congress.

• 2020 - Robert Kelly, vocal proponent of the Wideawake America Movement - a pro-human, anti-mutant movement - is elected President of the United States.

• 2022 - President Kelly announces he is backing Congressman Creed's proposed Mutant Control Act.
  
  • Bolivar Trask, a man credited with creating Earth's greatest defense in the form of the Sentinels, purchases a social media site and begins peddling conspiracies of a mutant replacement theory. This move is hailed by Congressman Creed and others of like mind.
  • A new Brotherhood of Mutants forms in the wake of resurging Neo-Purifier beliefs.

• January 2023 - Present day.