Look, we all love the Legion of Super-Heroes. There's no argument there. But it's nearly impossible keeping everything straight, because the continuity has been disrupted so many times. Not to say you can't enjoy the stories by themselves regardless... there's nothing wrong with that... but it's incredibly daunting if you want to try understanding them in context. This has the unfortunate side effect of making many new readers not want to get into the Legion, because it's so confusing. It's especially hard trying to decipher all of their history in little bits and pieces.
There are three different primary incarnations of the Legion, each of which takes place during the 30th Century in its own exclusive continuity. Legion of Super-Heroes One, Legion of Super-Heroes Two, Legion of Super-Heroes Three. Problem, they all occupy the same place in history. Originally, these were all supposed to exist in different possible futures for the DC Universe. Final Crisis establishes that they are all actually from different realities, each interacting with the past of the primary one because of flaws in the time travel.
- 1958: First appearance of the original Legion of Super-Heroes, a club of teenagers from the 30th Century who have based their heroic ideals on the career of Superboy, who is then admitted into their ranks. They were founded by core members Cosmic Boy, Lightning Lad and Saturn Girl. Their sponsor R.J. Brande, who thought of the idea, is explicitly inspired by the adventures of Superboy and Supergirl.
- 1961: The Adult Legion is introduced, older versions of the Legionnaires from a slightly further future who team up with Superman in his adulthood. This plot device also completely defined future Legion chronology, and determined the paths of the characters, including many romances
- 1986: Crisis on Infinite Earths. The original team is separated into two distinct alternate timelines. The regular timeline continues normally from here, but another version of the team divergent from this point will reappear twenty years later after Infinite Crisis.
- 1986: The Man of Steel retconned Superboy out of continuity, so that Clark Kent wouldn't become a hero until much later when he becomes Superman. This created problems for the Legion's origins which depended on his existence.
- 1987: To repair the discrepancies, the Time Trapper is said to have intentionally altered the timeline. He creates a new Superboy in a Pocket Universe, and makes it so that whenever the Legion travels back in time, they were instead shunted to this alternate reality. He is killed in action.
- 1990: Mon-El defeats the Time Trapper and destroys his physical form, which undoes all of his work from history. This leads to a future where the Legion never existed, and the wizard Mordru conquered all with no one to oppose him. In the Mordruverse, the former Legionnaires fight as a rebellion against his totalitarian regime. Glorith stepped in to take the Trapper's place in history, and brought back the universe as it had been. This led to some key differences, most notably Valor taking the place of Superboy in Glorithverse continuity.
- 1994: Zero Hour. The original Legion is ostensibly destroyed and erased from existence, because entropy wrecks their version of the future in End of an Era. They are replaced by a new incarnation of the Legion of Super-Heroes starting over with a continuity reboot.
- 2004: The second Legion is erased from continuity because of a cosmic Crisis, and they are replaced by the third Legion of Super-Heroes.
- 2006: Superman's history with the Legion is reestablished as a result of Infinite Crisis. The first Legion returns to continuity during the Lightning Saga.
- 2007: Superman travels to the future to help the Legion in Superman and the Legion of Super-Heroes, elaborating on his past with them.
- 2008-09: Superman travels to the future to help the Legion against Superboy-Prime in Final Crisis: Legion of 3 Worlds. Brainiac 5 explains that the other two Legions are from parallel worlds in the multiverse, who met after the Crisis on Infinite Earths to help protect the Tornado Twins from Professor Zoom.
- ↑ Adventure Comics #247
- ↑ Superboy #147
- ↑ Superman #147
- ↑ Superman #295
- ↑ Legion of Super-Heroes (Volume 2) #300
- ↑ Crisis on Infinite Earths #10
- ↑ The Man of Steel #1
- ↑ Legion of Super-Heroes (Volume 4) #4
- ↑ Legion of Super-Heroes (Volume 4) #5
- ↑ Legion of Super-Heroes (Volume 4) #61
- ↑ Legion of Super-Heroes (Volume 4) #0
- ↑ Teen Titans/Legion Special #1