Today is the official launch of Marvel's big 2012 summer event, Avengers vs. X-Men, the culmination of eight years of stories for both major lines at Marvel Comics: the Avengers and, well, the X-Men. With few exceptions, the stories of the two teams have remained largely separate since 2005's House of M, but with Marvel pushing Avengers vs. X-Men as a tool to bring in new and lapsed readers, people might be curious about the sequence of events that led to this point. While the #0 issue sets up the major emotional crises surrounding the Scarlet Witch and Hope, and #1 does a good job setting up the overall story, it's still the culmination of a great deal of past continuity. And I'm here to catch you up.1977: The Dark Phoenix Saga

One of the first major longform storylines in Bronze Age comics was Chris Claremont and John Byrne's "Dark Phoenix Saga" in the pages of X-Men. There are numerous recaps of the story available on the Internet, but here's the short version: after her seeming death, telepath Jean Grey's telekinetic powers increase to the point of godhood, which manifests in a fiery bird projection. After saving the universe from a neutron galaxy in the middle of the spacefaring Shi'ar Empire's M'Kraan Crystal, her powers increased even more, until the mental manipulation of the Hellfire Club's Mastermind brought out her "dark side," turning her into the "Dark Phoenix" that was consumed by her own power.

Once she crosses the line and destroys a fully populated world with six billion souls, she gets hunted by the Shi'ar, and eventually takes her own life in a moment of clarity to stop herself from killing everybody. The Phoenix was later revealed to be a cosmic force of death and rebirth that possessed Jean Grey rather than a natural extension of her telekinetic abilities; the real Jean Grey later returned and was killed after again merging with the Phoenix at the end of Grant Morrison's New X-Men run.

2004: Avengers: Disassembled

2004's Disassembled event had a core narrative in Avengers #500-503, by AvX cowriter Brian Michael Bendis and artist David Finch (with some assists from Olivier Coipel, also an artist on AvX). In short, a few years before this story, Avenger Scarlet Witch had discovered that her children with robot husband the Vision were actually magical constructs of her reality-altering powers, and then slowly and secretly went insane, culminating in the attack that destroyed Avengers Mansion and killed the Vision. In the end, Doctor Strange exposed the true nature of the attack, and Scarlet Witch was secreted off by her father, X-Men Magneto.

Six months later, the Avengers reformed as the New Avengers under the same creative team, including new members with few ties to Avengers history such as Spider-Man, Wolverine and Luke Cage.

Meanwhile, Grant Morrison's run on New X-Men wrapped and was replaced with new flagship title Astonishing X-Men by Buffy the Vampire Slayer mastermind Joss Whedon and Planetary's John Cassaday, which reintroduced the team as superheroes rather than a mutant rescue group, bringing back the old costumes and re-embracing a more classic milieu for the team.

2005: House of M

In 2005, the summer event book House of M by Bendis and Coipel featured an alternate reality created by Scarlet Witch's reality-altering powers where mutants are the dominant species. It was eventually revealed that it was created at the urging of Scarlet Witch's brother, also-Avenger Quicksilver. Right before she changed the world back to normal, she issued the edict of "no more mutants," depowering the entire mutant population, except for two hundred individuals (how those specific mutants escaped this was never revealed). The Avengers and X-Men decided to keep Wanda's actions a secret from the world.

2006: Civil War

While the remaining mutant population were placed under government surveillance at the X-Men's Westchester mansion, the Avengers and the rest of the superhero community had a major crisis of conscience after the near-destruction of Stamford, Connecticut by a super-powered being in Mark Millar and Steve McNiven's Civil War. A superhero registration law soon passed, and the superhero community divided between Captain America, fighting registration, and Iron Man supporting it. Iron Man won, Captain America got shot for totally unrelated reasons, and the Tony Stark Era began. Stark essentially ran the entire superhuman community and leads the government-sponsored Mighty Avengers, while the remainder of Steve Rogers's allies fights underground as the New Avengers.

2007: World War Hulk and Messiah CompleX

A number of plotlines simmered in the background of 2007's major event, World War Hulk, written by Greg Pak with art by AvX artist John Romita Jr. This main event centered on the Illuminati -- a shadow council running the superhuman community consisting of X-Men founder Charles Xavier, Avenger Iron Man, Inhuman king Black Bolt, King Namor of Atlantis and Sorcerer Supreme Dr. Strange -- team ingup with S.H.I.E.L.D. to solve the Hulk problem once and for all by shooting him into space at a peaceful planet. Instead, he got directed to a gladiator planet and came back with an army to smash the hell out of Manhattan. The superheroes won, eventually.

Meanwhile, on the X-Men side, the first mutant since House of M was born, and born with her powers already active, rather than seeing them manifesting at puberty. The anti-mutant hate group the Purifiers burned down the Alaskan town where she was born, but not before she was spirited away by X-Men leader Cyclops's time-travelling son Cable, who ran a gauntlet with her from the various groups attempting to locate her, including the Purifiers, Mister Sinister and the Marauders, the turncoat Bishop (who claimed that this messiah baby led to his dystopian future) and the X-Men themselves. Eventually, Cable escaped into the future with the child with his father's blessing, and the mutant community regained hope for their future.

2008: Secret Invasion

In 2008's Secret Invasion, the New Avengers uncovered a years-old alien conspiracy to take over the Earth. The Skrulls, a group of alien shapeshifters who lost their homeworld years ago, had a fringe religious sect intent on making Earth the new Skrull homeworld. Using shapeshifting subterfuge, they infiltrated the superhero community they had clashed with so many times before in order to destroy it from within. The superheroes, as they do, eventually saved the day, but the final kill shot was given to Spider-Man villain and Thunderbolts director Norman Osborn, leading to the next year of stories.

On the X-Men side of things, after the mansion was destroyed (again) as a result of Messiah CompleX, the group relocated to sunny San Francisco under the unquestioned leadership of Cyclops.

2009: Dark Reign, Utopia and Messiah War

After Norman Osborn took control of the superhuman community in the wake of the Secret Invasion, he formed a new group, HAMMER, to replace Tony Stark's SHIELD, and an anti-Illuminati alliance called the Cabal with supervillain kingpin the Hood, Doctor Doom, Loki, X-Man (and Cyclops's girlfriend) Emma Frost and King Namor of Atlantis (yeah, he pulled double duty). Osborn also put together his own team of dark Avengers (in another Avengers title written by Bendis), while the former pro- and anti-registration forces alike teamed up in the New Avengers title.

Eventually, Osborn decided to pick a fight with the mutant community, leading to a huge brawl in San Francisco until Cyclops raised the ruins of Magneto (who had recently returned to the X-Men declaring his fealty to Cyclops's leadership)'s former asteroid base Asteroid M into the San Francisco Bay, forming his own island nation outside of Osborn's authority. This island was named Utopia, also the name of the Dark Avengers/Uncanny X-Men crossover written by AvX co-writer Matt Fraction in which these events occurred.

Meanwhile, X-Force was sent into the future to check up on Cable and the messiah baby (now named Hope). They fought Apocalypse together and went their separate ways, with X-Force (led by Wolverine) returning to inform Cyclops that Hope was not going to be a child when she returned, since she'll likely have grown far more in the future. Hope was also shown to have red hair and green eyes -- the exact same body features as the deceased Jean Grey.

2010: Siege and Second Coming

In early 2010, after the original Captain America returned, Norman Osborn decided to pick another fight, this time with Thor and the Asgardian Gods in Oklahoma. The Avengers came to rep for their boy, beat the crap out of everybody, exposed Osborn as a lunatic on live television and got the Steve Rogers Era to kick off, which Marvel branded as the Heroic Age.

Simultaneously, Cable and Hope finally returned to the present day, at the remains of the Xavier school in New York. They traveled from the east coast to west while the time-traveling mutant-hating robot Bastion tried to kill them. Nightcrawler died to bring her to Utopia, Bastion attacked San Francisco and enclosed it in a big forcefield dome, Cable and X-Force went to the future Bastion was from to try to kill him, a bunch of stuff blew up, Cable sacrificed himself to save his surrogate daughter, and Hope revealed that (as many fans expected) she was the Phoenix, saving the day.

2011: Fear Itself and Schism

In 2011, after about a year of the Heroic Age, Sin -- the daughter of Captain America's dead archenemy the Red Skull -- discovered some of her father's journals and used them to free the Cul, the Serpent, brother of Thor's father Odin and hidden Norse God of Fear. The Serpent called the Worthy, eight ancient spirits that possessed hammers that, when wielded by existing Marvel Universe characters, transformed them into vessels for that power, much as Donald Blake uses the Hammer of Thor to become Thor. One such character was the Juggernaut, Cain Marko (Xavier's brother), who attempted to destroy the X-Men and was repelled by X-Man Colossus making a deal with the evil god Cyttorak to become the new Juggernaut, since the original one had changed his allegiance to the Serpent. Over on the Avengers camp, Tony Stark got drunk again and used that as a sacrifice to get Odin to let him build some badass weapons for the Avengers, who used those badass weapons to beat up the Worthy while Thor died fighting the Serpent. (He came back a few months later; writer Matt Fraction has actually stated the main theme of Fear Itself was the impermanence of death).

Over with the X-Men, a new Hellfire Club composed of young children unleashed Sentinels on the X-Men, forcing the group into a philosophical quandry with Cyclops believing that the young mutants under his charge were training to become soldiers due to the necessity of a harsh life, while Wolverine supported the idea that the children should be allowed to be children and nobody should have to suffer like he did. In the end, the split became so untenable that Wolverine left with half of the mutant population to the ruins of Xavier's school to rebuild it as the Jean Grey School of Higher Learning; Hope, meanwhile, stayed behind with Cyclops on Utopia, where Cyclops assembled his "Extinction Team" of high-powered mutants with which he planned to both intimidate and save the world.

2012: Avengers vs. X-Men

The series Avengers: The Children's Crusade by Allan Heinberg and Jim Cheung, which began in 2010, finally concluded, resulting in both the exoneration and the return of the Scarlet Witch to regular life in the Marvel Universe. (It turns out that her insanity was masterminded by Doctor Doom.) In Avengers: X-Sanction, by Jeph Loeb and Ed McGuinness, Cable returns with his techno-organic virus threatening to kill him in 24 hours, armed only with the knowledge that if the Avengers kill Hope, they end up destroying the Earth. Eventually, Hope shows up and Cable seems to give in, and back on Utopia Hope cures her surrogate father of his techno-organic virus, leaving him recovering from his wounds.

Which brings us to now: the Phoenix is coming for Hope. The Avengers want to prevent it from coming at whatever cost; Cyclops believes it needs to come and use Hope as a vessel to rebirth the mutant race.

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