The Original Team
First Appearance: X-Men (1st series) #1
Members: Angel, Beast, Changeling, Cyclops, Havok, Iceman, Marvel Girl, Mimic, Polaris and Professor X
Membership History
Published in 1963, the very first issue of X-Men (1st series) debuted with Professor X and his students Angel, Beast, Cyclops and Iceman. At the opening of the first issue, all were already established members of the X-Men, with their backstories to be fleshed out years later in subsequent issues. Professor X set up the X-Men in a back-up story in #42, with Cyclops becoming the first X-Man. Iceman was the second to join, receiving his origin flashback story in issue #46 and Angel following soon after in #56. Beast was the last to join, though the issue with his flashback story debuted before Angel’s in #53. The last member of the original line-up was Jean Grey, aka Marvel Girl, who officially joined the X-Men during the first issue.
In 2013, All-New X-Men (1st series) #1 had an older Beast travel back in time to the events taking place in X-Men (1st series) #8. He convinced the original five students to travel to the future with him to see the consequences of certain actions on their part. The five remained in the future for a year or so, before they returned to the same point in time from which they had left in X-Men (1st series) #8. The details of this iteration of the team will be dealt with at a later point in this article.
It should also be noted that Sage would later be retconned into being a member of the team at this point. Whilst she wouldn’t debut until X-Men (1st series) #132 as Tessa, it would be decades until she officially joined the X-Men on an active roster in X-Men (2nd series) #109. It was explained that Xavier had recruited her around the same time he gathered the original five X-Men, 
but he saw something different in Sage than he did the others. He sent her to be a spy for him within the Hellfire Club and kept her double-agent identity a secret from the rest of the team. As this explanation essentially makes her an X-Man since the start, her presence in this article is limited to the rosters in which she actively appears.
This line-up was to last unchanged for a few years until Mimic joined in #27. Having debuted in #19, Mimic was the first new recruit to the X-Men and also the first non-mutant to join the team. His tenure was short, however, as he was kicked off the team by Professor X in #29 for his arrogance and insubordination.
The next new recruit to the X-Men was unique in that he joined and left with no one even realizing it at the time. Debuting in X-Men (1st series) #35, Changeling was working for the villainous 
organization Factor Three. After Factor Three was defeated, Changeling seemed to leave the X-Men’s lives, but in reality he approached Professor X, revealing that he was dying of cancer. Professor X had recently learned that the Earth was going to be invaded by aliens and wanted time to prepare for the battle. Changeling used his shapeshifting abilities to take on the form of the professor, whilst the real Xavier went into hiding to plan. All of this backstory was explained in issue #65, and later in in X-Men Hidden Years #8. At the time of publication, the reader was unaware of the switch, which apparently took place around X-Men (1st series) #40. Unfortunately, Changeling died in the guise of the Professor during a battle with Grotesk in #42 and no one was any the wiser. It wasn’t until #65 when it was revealed the real Xavier was alive and that Jean had known all along.
The next new member of the team was Lorna Dane, who first appeared in issue #49. When she 
first came across the X-Men, she had no idea she was a mutant and it was only when her latent gifts were triggered that she realized what she was. She remained an ally of the team for a few issues but was reluctant to join. This lasted until #60, when she finally realized that being a mutant meant she couldn’t live a normal life anymore. She initially took the codename Magnetrix but, after some teasing by the others, she opted for the now-infamous Polaris instead.
The final member of the original line-up was Cyclops’ previously unmentioned brother, Havok. Debuting in X-Men (1st series) #54, Alex Summers was attempting to lead a normal life until a villain captured him and used his energy-based powers for himself. After the X-Men rescued him, Alex hung around with them for a while until he realized he couldn’t go back to his usual life again and so he joined the team in issue #65 as Havok.
Although X-Men (1st series) was cancelled with #66, the title itself continued as a reprint title with #67, re-publishing the original issues. Over the next few years, the X-Men were reduced to being guest-stars in other titles, such as the Avengers or Fantastic Four. Years later, a series entitled X-Men Hidden Years was published that bridged the gap between #66 and the eventually release of new material with Giant-Sized X-Men #1 and X-Men (1st series) #94. The roster during this period remained relatively stable, with only Beast leaving the team to join the Avengers.
