Here's how Superman Returns fits in the overall Christopher Reeve Superman movie saga. Directed by Bryan Singer, Superman Returns premiered in 2006 and starred Brandon Routh as Clark Kent a.k.a. Superman, Kate Bosworth as Lois Lane, and Kevin Spacey as Lex Luthor. The film's critical reception was lukewarm, and Superman Returns' $391-million worldwide box office gross was considered disappointing by Warner Bros. The studio elected not to move forward with a sequel, ultimately rebooting the Superman movie series in 2013 with Zack Snyder's Man of Steel.

1978's Superman: The Movie pioneered the modern blockbuster superhero film and is still considered a benchmark of the genre today. Director Richard Donner cast the then-unknown Christopher Reeve as the Man of Steel and Margot Kidder as Lois Lane, and surrounded them with some of the finest actors of the era - including Marlon Brando as Jor-El, Glenn Ford as Jonathan Kent, Jackie Cooper as Perry White, and Gene Hackman as Lex Luthor. Along with groundbreaking visual effects that made audiences "believe a man can fly," Superman: The Movie was a global blockbuster. The sequel, Superman II, was shot back-to-back with the original film, but Donner was fired by producers Alexander and Ilya Salkind over budgetary issues and was replaced by Richard Lester. Superman III, which teamed Reeve with comedian Richard Pryor, underwhelmed in 1983, and the low-budget Superman IV: The Quest for Peace was a disaster that ended the franchise.

Related: Why Superman V With Christopher Reeve Never Happened

After several failed attempts to reboot the Superman films by directors Tim Burton, McG, Brett Ratner, and J.J. Abrams, Bryan Singer was hired by Warner Bros. after he delivered two back-to-back X-Men blockbusters for Fox. Instead of rebooting the franchise, Singer, who was a lifelong fan of Donner's Superman, opted to create a continuation of the Christopher Reeve films. Singer cast Brandon Routh as Superman in part because of the young actor's uncanny resemblance to Reeve, who died in 2004 after a tragic accident left him a paraplegic who heroically crusaded for spinal cord and stem cell research. Kate Bosworth as cast as Lois Lane and Kevin Spacey, who worked with Singer in 1995's The Usual Suspects, was cast as Lex Luthor. Both actors were meant to be the same versions of their characters played by Margot Kidder and Gene Hackman. To hammer this home, Singer repurposed old footage of Marlon Brando so that Superman's birth father's hologram could appear in the film.

Brandon Routh and Kevin Spacey in Superman Returns

Superman Returns' place in the Reeve franchise is unusual. Singer vaguely set his film five years after Superman II, with Kal-El abandoning Earth for that time period in order to search for the ruins of his doomed home planet of Krypton. Singer's movie ignores Superman III and Superman IV, essentially jettisoning them from canon. But the effect is strange; for instance, Spacey's Luthor visits the Fortress of Solitude to steal its crystal technology. Hackman's version of Lex went to the Fortress in Superman II, but Spacey's version doesn't fully acknowledge this fact. Further, Reeve's Superman movies obviously take place in the late 1970s/early 1980s, but Superman Returns' hazy "five years later" setting is an unusual hodgepodge where Metropolis seems frozen in time yet has modern technology like flatscreen TVs in the Daily Planet.

Regardless, the chronology Singer was going for was Superman: The Movie leading to Superman II, and then his Superman Returns happened five years later, replacing Superman III and Superman IV simply never happened. If Superman Returns' planned sequel, Superman: The Man of Steel, had gone forward, it would have essentially been the new Superman IV.

Disappointingly, Brandon Routh didn't get to reprise his role in a sequel - until fate took a turn 13 years later. Routh, who joined The CW's Arrowverse series and played Dr. Ray Palmer a.k.a. The Atom in DC's Legends of Tomorrow, was asked to play his version of Superman once more in the Crisis On Infinite Earths crossover. Routh's comeback as Superman instantly made Superman Returns and the Christopher Reeve films canonically part of the Arrowverse, with their world designated as Earth-96 in the Multiverse.

Things gets even more interesting because during the Crisis, Routh's Clark Kent told of "several go-arounds" he had with Lex Luthor and also that "I once went nuts and fought myself," indicating that the events of Superman III - when the good Clark Kent fought an evil version of Superman - did happen. So it seems that the Arrowverse retconned the Reeve/Routh Superman continuity so that Superman III and possibly even Superman IV did happen after all, and possibly now take place after Superman Returns.

Next: Superman Returns: What Happened To Brandon Routh's Clark Kent After The Movie