Erik Lehnsherr visits America for the first time and sees the Statue of Liberty. Sometime between 1949 and 1962, he returns to Europe, disillusioned with America's image as the land of "tolerance and peace".
Plans are approved by President John F. Kennedy to build an underground bunker below the White House during its extensive renovation undertaken by his wife Jackie. The bunker, code-named "Cocoon", is designed to help the president's brother, Attorney-General Robert F. Kennedy, hone his mutant abilities. All funding for this project will be attributed to "private living quarters".
U.S. Major General Edwin Partridge retires from the Army. He becomes a far right-wing activist.
A young Bolivar Trask hypothesizes the link between traceable higher-order brain function and certain genetic mutations.
Moira MacTaggert begins investigating Sebastian Shaw, eventually leading her to discover mutants and meet Charles Xavier.
Charles Xavier earns a PhD in Genetics from Oxford University.
Sebastian Shaw and the Hellfire Club coerce Colonel Hendry to put missiles in Turkey. Later on, they coerce the Soviet military to put missiles in Cuba in an attempt to start a nuclear war between humans, so that mutants can become the dominant species on Earth.
Charles Xavier plans to establish a school and sanctuary for mutants.
The Brotherhood of Mutants free Emma Frost, who subsequently joins them.
Following the Cuban Missile Crisis, the Kennedy administration authorizes the Central Intelligence Agency to establish Project WideAwake, a covert task force to investigate other X-Gene cases and their prevalence across the United States. While its mission strictly revolves around identification and research of mutants, it exercises paramilitary autonomy from the President's mandates.
Edwin Partridge, a former Major General in the U.S. Army and a far right-wing activist, gains (through his contacts in the military) proof of mutant involvement during the Cuban Missile Crisis, including amateur photos and an 8mm film.
Edwin Partridge, addressing a rally of his supporters, makes allusions to the existence of mutants and their potential threat.
According to the Warren Commission, Erik Lehnsherr allegedly recruits Lee Harvey Oswald to murder Edwin Partridge around this time.
An assassin kills Edwin Partridge. Partridge's death incenses his supporters, who become more virulent and active.
Robert Kennedy orders a pair of prototype psychic earshields to isolate and control his psionic powers. The order is approved on August 22.
Lee Harvey Oswald becomes employed at the Texas School Book Depository.
President John F. Kennedy arrives in Dallas, Texas on a fundraising campaign for the upcoming 1964 presidential election. While in Dallas, he plans to make a speech at the Trade Mart addressing the mutant rumors. Prior to his arrival, the radical right-wing group Friends of Humanity distribute pamphlets decrying Kennedy's "crimes", including lacking a hardline policy for dealing with potential mutant threats.
As his motorcade reaches Dealey Plaza, John F. Kennedy is assassinated. Erik Lehnsherr, using his magnetic powers, makes a failed attempt to save him. Several witnesses, including Marie Ellen Dodge and Gavin Lindhardt, place Lehnsherr on the plaza's Grassy Knoll during the assassination.
The 'Bent Bullet' is taken as evidence.
Lee Harvey Oswald, who has been accused of killing President John F. Kennedy, is murdered by nightclub owner Jack Ruby while in the process of being transferred to a more secure location. Ruby is soon arrested.
Warren Commission members Earl Warren and Gerald Ford arrive in Dallas to interview Jack Ruby. Ruby, who claims not to remember much about his whereabouts and actions just before or after killing Oswald, states to both Warren and Ford that he had recently been injected with some sort of unusual vaccine. Ruby's testimony is ultimately omitted from the Commission's final report.
Following the Kennedy Assassination, members of the Central Intelligence Agency, the Secret Service, and other government officials establish the Federal Council on Mutant Activities (FCMA).
After initially refusing to cooperate with the Warren Commission, the Central Intelligence Agency finally offers "full cooperation" sometime during the month. This is mainly for identifying Erik Lehnsherr as the person in Marie Ellen Dodge's photograph of the Grassy Knoll.
Jack Ruby is sentenced to death for murder with malice of Lee Harvey Oswald.
Jack Ruby becomes violently ill, and is admitted to Parkland Memorial Hospital after prison medical staff state that he is suffering from what appears to be pneumonia. While being operated on, rampant cancer growth is seen on his vital organs.
Project WideAwake agents are quietly dispatched to locate and apprehend Erik Lehnsherr.
Jack Ruby dies from a pulmonary embolism associated with lung cancer.
Erik Lehnsherr, while in rural New York, turns himself in to police.
The Warren Commission publishes its 688-page report.
President Lyndon Johnson notes in a closed-door meeting with the Warren Commission that their prime suspect - Erik Lehnsherr - was in custody.
Erik Lehnsherr is found guilty of first-degree murder and conspiring to assassinate John F. Kennedy. He is sentenced to two consecutive life sentences in a federal correctional facility without the possibility of parole.
U.S. Senator Edward M. "Ted" Kennedy was involved in a plane crash in which one of his aides and the pilot were killed. He was pulled from the wreckage by fellow senator Birch E. Bayh II and spent weeks in a hospital recovering from a broken back, a punctured lung, broken ribs, and internal bleeding.
Charles Xavier opens the Xavier School for Gifted Youngsters at his family's Westchester mansion.
Trask Industries revolutionizes the world of prosthetics through DNA-generated artificial limbs.
Robert Kennedy, while campaigning for President, is interviewed by his biographer regarding his mutant abilities.
Most of the male students and teachers at Xavier's School have been drafted in the Vietnam War by this date. Charles, falling into depression, becomes addicted to a drug designed by Hank to allow him to walk, but it suppresses his powers. The school and mansion fall into ruin.
Trask Industries B3-VXC Archival Footage is filmed.
After breaking out of several prisons during the 1960s, Magneto is finally subdued by a specialized prison developed by Trask Industries. It is located in the Pentagon, 1,320 ft below the Earth's surface, and is composed of industrial-grade polymers and concrete to negate Magneto's powers.
Erik Lehnsherr is publicly revealed as having participated in the John F. Kennedy assassination 10 years previously.
Wolverine from the alternate future awakens in his younger body.
Logan, Charles, Hank and Quicksilver break Erik out of his Pentagon prison.
The X-Men prevent Mystique from killing Bolivar Trask in Paris however, Erik turns against them. 
Trask Industries unveils the Sentinels Program.
Wolverine and Hank fight Erik and a Sentinel while Charles tries to convince Mystique to spare Bolivar Trask at the White House.
The Sentinels Program is cancelled. Bolivar Trask is arrested for selling military secrets.
Mystique, under the guise of William Stryker, raises Logan from the Potomac River.
United States Congress passes the HCA (Homeland Containment Act), deploying Sentinels to the top 5 most densely populated cities in the U.S.
Sometime during this year, the Federal Council of Mutant Activities (FCMA) publishes an important report regarding mutants.
While serving in Vietnam, Victor Creed kills a senior officer, and Logan defends him from retaliating soldiers. The two are arrested and are eventually sent to be executed by a firing squad. However, their regenerative healing abilities prevent them from being killed.
Logan and Victor Creed meet William Stryker and join Team X.
Charles Xavier and Hank McCoy reopen the school for mutants. A new generation of teachers and students are welcomed.
The Vietnam War ends.
Charles Xavier appears in Washington, D.C. in a private closed session to plea for mutant freedoms.
Logan quits Team X during a mission in Nigeria.
The Vietnam War ends.
Based upon the FCMA's findings from two years ago, the Homeland Mutant Response Division is formed.
Scott Summers begins to attend Xavier's school after his powers accidentally manifest during a confrontation with a high school bully. 
Magneto is living a normal life in Poland with a wife and daughter hiding his identity. He is forced into using his powers and is exposed. His wife and daughter are accidentally killed by the Polish police.
Mystique saves Nightcrawler from a mutant fighting ring in Germany, she takes him to see Charles Xavier.
Apocalypse recruits Magneto, Storm, Archangel and Psylocke to be his horsemen of Apocalypse. They arrive at the X-Mansion which results in Charles getting captured, the death of Havok and Quicksilver having to save all the students as the school explodes. 
Jean Grey, Cyclops, Beast, Moria MacTaggart, Mystique, Quicksilver and Nightcrawler are captured by William Stryker. As they escape Jean frees Wolverine from a box where he was being experimented on and cuts down everyone in his path to escape, before he leaves, Jean restores a piece of his memory. 
After escaping the group battles and defeats Apocalypse and his four horsemen in Egypt. 
The X-Men are officially formed with Cyclops, Jean, Storm, Quicksilver, Nightcrawler, Beast and Mystique as their field leader. 
Popular televangelist Minister Bob Bell calls mutants "God's Curse".
Charles Xavier and Erik Lehnsherr visit Jean Grey.
Chernobyl disaster causes many babies born to develop mutations.
Peter Rasputin, later known as Colossus, is born.
Chernobyl disaster causes many babies born to develop mutations.
Piotr Rasputin, later known as Colossus, is born.
Mutants protest at the Berlin Wall in West Germany, and East Germany is made a mutant zone.
Trask Industries and the Federal Bureau of Investigation unveil a way to identify mutants using DNA from crime scenes. Trask Industries, off the record, uses the DNA to build Mutant Registry, with plans to sell the information to wealthy world governments.
The Weapon X Program is reopened by a secret government agency, it begin creating mutants through brutal and sadistic methods, to sell off to the highest bidder. Angel Dust and Ajax are among the first created, with the later becoming a doctor for the company.
Angel is killed by Sentinels during an Occupy Wall Street march on the X-Mansion.
A magnitude 5.8 earthquake shakes Washington, D.C. It is the largest east of the Rocky Mountains since 1897.
Blink breaks 30 mutants out of Trask prison camps.
Wolverine having been hiding in the Yukon wilderness encounters a group of hunters. Yukio tracks him down telling him that Ichirō Yashida (now the head of a billion dollar company) would like to say goodbye.
Yukio and Logan travel to Japan, Ichirō tells Logan he wants to transfer his healing power out of his body and into his so Logan can die peacefully. Viper places a parasite in Logan's body, stopping his healing factor from working.
Ichirō dies, his funeral is attacked by Yakuza and Logan is forced to save Mariko Yashida, the two go on the run, eventually becoming intimate.
Mariko is captured by the Yakuza, Logan removes the parasite effecting his powers and he and Yukio fight Shingen Yashida. He was responsible for hiring the Yakuza, due to Ichirō giving his company to Mariko instead of Shingen.
Wolverine and Yukio attack the compound holding Mariko, fighting off Black Hand Ninjas.
Ichirō is revealed to be alive, using an armoured exoskeleton, he fights Wolverine and nearly kills him by absorbing his healing but he is saved by Mariko. Yukio kills Viper and Wolverine kills Ichirō but loses his Adamantium claws. 
Wolverine and Yukio take a plane to go back to America. 
Trask Industries unveils groundbreaking ability to create a hybrid gene with mutant DNA.
Wade Wilson and Vanessa Carlysle get engaged and Wade finds out he has terminal cancer. Desperate he, agrees to an experimental procedure from and is given enhanced abilities such as a healing factor. But he also get his body disfigured. Wade starts searching for Ajax, who gave him the ability, to return his previous appearance.
Wade Wilson catches up Ajax's convoy on the highway and attacks them. Wade captures Ajax but Colossus and Negasonic Teenage Warhead arrive and Ajax manages to escape. Colossus tries to lead Deadpool to X-Mansion but he escapes.
Deadpool, with a help of Colossus and Negasonic Teenage Warhead, defeats Ajax and his bodyguards on the scrapyard. Wade kills Ajax and reunite with Vanessa.
Dr. Gregory D. Burnett revolutionizes a method of growing synthetic stem cells.
Laura Kinney is born based on DNA from Wolverine at the Transigen lab in Mexico. She is part of the "X-23" project with other mutant children. 
Kitty Pryde sends Wolverine back in time to 1973 to stop Mystique from killing Bolivar Trask.
The remnants of the X-Men and Free Mutants are massacred in China.
Logan successfully manages to prevent Trask's assassination in 1973 and indirectly changes history itself, erasing the original timeline from existence.
The X-Men (including Jean Grey and Cyclops) are all present at the X-Mansion.
The "X-23" children, including Laura Kinney, are subjected to experiments by Dr. Zander Rice
Charles Xavier suffers a massive psychic seizure that injures over 600 people in Westchester along with killing several members of the X-Men. Wolverine takes him to Mexico, hiding him away so Charles's deteriorating mind can't hurt anybody else.
Some of the "X-23" children escape from Transigen with the help of their nurses, after a kill order is put on them. The escapees plan to meet at place called "Eden". 
Logan is working as a limo driver, his healing factor has almost stopped working and the Adamantium in his body is poisoning him. He and and Caliban take care of Charles Xavier who needs to be medicated so his mind can't hurt anybody like at Westchester. 
Logan encounters Donald Pierce the head of Transigen's mercenary unit called The Reavers, he tells Logan he's looking for a girl, one of the escaped X-23 children. 
Logan eventually comes into contact with this girl named Laura, she is revealed to be Logan's daughter. After a fight with the Reavers, Logan, Charles and Laura go on the run, going to "The Eden".
In Oklahoma, The Reavers track down the trio, due to a kidnapped Caliban. Charles has a seizure, but is tranquilized and the trio escape. Logan finds out that "The Eden" is based on a comic book and becomes angry and sceptical.
The trio run into the Munson family and end up helping them on the road. In return the family invites them to dinner. The Munson family ranch is attacked by "X-24" a younger stronger clone of Wolverine, made by Transigen. In the fight, the Munson family, Caliban and Charles Xavier are all killed, but Laura and Logan manage to escape, but Logan is heavily injured.
Logan buries Charles Xavier, but passes out due his injuries and Laura takes him to a doctor. Laura manages to convince Logan to take her to "The Eden", which they find is a real place run by the mutant Rictor that houses the X-23 children.
Laura, Rictor and the other X-23 children plan to leave "The Eden" and head into Canada where a sanctuary is waiting for them. The Reavers arrive to capture them and a chase ensues in the forrest. 
A weakened Logan, is forced to take a mutant serum to regain his powers, he rushes to save the children and his daughter. He and Laura kill most of the Reavers, until X-24 arrives.
X-24 manages to overpower Logan and impale him on a tree, but Laura kills him using an Adamantium bullet. Logan dies in Laura's arms and she and the other children he saved bury him, before continuing on to Canada.
Laura turns the cross on Logan's grave into an X to honour him as the last of the X-Men.
In X-Men, Charles tells Logan that he met Erik when he was 17 years old. In X-Men: First Class, they met each other in their early 30's.
In X-Men, Charles doesn't know why he can't find Erik with Cerebro, whilst in X-Men: First Class he witnesses the effects of the helmet.
In X2: X-Men United, a human Hank McCoy can be seen on a television screen debating the issue of mutant rights alongside a "Dr. Shaw". In X-Men: The Last Stand, Kelsey Grammer portrays Beast in full blue costume. (There was a scene written in the screenplay for X2 that showed McCoy undergoing his Beast transformation in the scene where Xavier activates Stryker's Cerebro to target all the mutants, but it was cut early on.)
The X-Mansion in X-Men: First Class is not the same as the original building in the original trilogy. However, it can be assumed that it was renovated and expanded to serve as a school.
In X-Men: The Last Stand, Moira MacTaggert is a Scottish doctor working at Muir Island's genetic facility, while in X-Men: First Class, she is an American agent working for the CIA.