In 1979, fresh off the blockbuster success of Superman: The Movie, cast and crew gathered again to finish work on what was now one of the most-anticipated sequels of all time. Superman II had long been planned as a follow-up to the first film, to the point that the films were actually shot simultaneously. But by the time finishing the sequel was on the agenda, the entire process was embroiled in turmoil that led to on-set tension, contract disputes, and—decades later—one of the most famous director's cuts in the history of cinema. From director swaps to different endings, here are 13 facts about the making of Superman II.

1. Much of Superman II was shot alongside Superman: The Movie.

Ned Beatty and Gene Hackman in Superman II (1980).Warner Home Video

Making the first major motion picture to star Superman was ambitious in itself in the late 1970s, but producers Alexander and Ilya Salkind were thinking bigger even before Superman: The Movie flew into theaters in 1978. The plan throughout the early production process was always to make two films, and to shoot them simultaneously. That meant Superman director Richard Donner and the film's cast and crew had to keep strict track of continuity while shooting, because they might end up spending a day filming several scenes on The Daily Planet set, for example, that were meant to span various points in two different feature films. This simultaneous shooting schedule also meant that by the time Superman: The Movie was in theaters, much of Superman II was already filmed, and just waiting for Donner to complete it. That was the plan, anyway ...

2. Richard Lester was brought in very early to replace Richard Donner.

As production on Superman and Superman II wore on, director Richard Donner clashed frequently with the Salkinds and their on-set producer, Pierre Spengler, over various aspects of the production, including his supposedly outlandish expenditures on the movie. For his part, Donner always claimed that he had no idea how much money he was spending, because the Salkinds never provided him with a concrete budget. The tension got so bad at one point that Donner and Ilya Salkind stopped speaking to each other, and the younger Salkind tried to get Donner fired by writing a letter to his agent claiming that the director was in breach of contract. The letter carried no weight, so Donner kept working. And Warner Bros. Pictures, for its part, was impressed enough with Donner's footage that they added some financial assistance to the shoot.

But that didn't stop Salkind from trying to put his director in check. Instead of firing Donner, Salkind decided that perhaps he could bring in a second director to "assist" Donner—someone who worked more in line with the Salkind style. He settled on Richard Lester, most famous at the time for The Beatles movie A Hard Day's Night, and offered the filmmaker the opportunity to recoup some money he was owed by the Salkinds from The Three Musketeers, which he had directed years earlier. Lester agreed, and by the summer of 1977 he was on the Superman set directing second unit footage and apparently, at least at first, getting along very well with Donner.

3. In improvised backstory convinced Terence Stamp to sign on to play General Zod in Superman II.

Terence Stamp, photographed in 1965.Larry Ellis/Express/Hulton Archive/Getty Images

Though Superman villain Lex Luthor (Gene Hackman) was still around for the sequel, Superman II was an adventure that required a bit more super-powered might from its villain, and therefore introduced the Kryptonian criminal General Zod and his two loyal lieutenants, Ursa and Non. To play Zod, Donner sought an actor with real presence and power, but when Terence Stamp was suggested, the director was sure Stamp would have no interest.

Then the pair met and, according to Donner, they bonded over a mutual experience in transcendental meditation, which they'd both just studied. As Donner began to pitch the Zod character, he made up a backstory for him on the spot, which apparently intrigued Stamp enough to get him to sign on for the film.

"He accepted it as a challenge, something different for himself, and he jumped on board," Donner later recalled.

4. Richard Donner was fired from Superman II via telegram.

Superman was released over the holiday season of 1978 and quickly became both a commercial and critical success. It was a massive hit for the Salkinds and Donner that also ultimately became one of a select group of films (it arrived a little more than a year after Star Wars) that helped usher in the blockbuster era of American cinema. Despite a few ongoing disputes—including a lawsuit from Superman screenwriter Mario Puzo, claiming he was owed a larger share of the film's earnings—everyone involved seemed largely pleased with the result. Then Donner spoke to the press.

In December of 1978, Variety columnist Army Archerd spoke to Donner about the success of Superman and the upcoming sequel, much of which Donner had already shot throughout the massive simultaneous production of 1977. In the course of their conversation, Donner attempted to assert more control over Superman II, to the point that he issued what amounted to an ultimatum: If producer Pierre Spengler was returning to finish Superman II, then Donner wouldn't be part of it.

The Salkinds, who already had a tense relationship with Donner, didn't back down. Ilya Salkind's close personal friendship with Spengler, combined with his rocky connection to Donner, meant that he and his father chose Spengler.

“Pierre is a childhood friend,” Ilya Salkind said. “We’ve known each other a long time. When he said it was on his terms, I said to my father, ‘We can’t work with a guy like that.’ It was a very simple decision. It was based on emotion more than anything else." In March of 1979, Donner received a telegram informing him that his services would no longer be required on Superman II. Richard Lester would take over the film.

5. The Superman cast was furious when Richard Donner was fired.

Richard Donner arrives at the premiere of 2006's Superman Returns in Westwood, California.Kevin Winter/Getty Images

The cast of Superman: The Movie left the massive shoot for the film with the understanding that they'd be coming back at a later date to finish Superman II under the leadership of Donner, whose passion for the material many of them had come to admire. Instead, they returned to find their director fired, and they weren't happy.

Stars Christopher Reeve and Margot Kidder both lashed out at the Salkinds in the press. Reeve referred to them as "untrustworthy" in an interview with Time Out and Kidder told People: "If I think someone is an amoral a**hole I say so." Gene Hackman, who'd only been available for a limited window to shoot his Lex Luthor scenes during the first round of production, turned down offers to come back for reshoots.

Donner himself retreated from Superman and tried to take his mind off the process. After a year off, he took on a much smaller film, Inside Moves, to shift his focus. According to Donner, though, he was at one point approached to rejoin Superman II via a shared director credit with Lester, and decided to view some of Lester's footage from the film. The director got part of the way through the opening Eiffel Tower set piece and left the room.

"I said forget it," Donner later recalled.

6. Richard Lester completely restructured Superman II.

Superman: The Movie famously borrowed its finale set piece—in which Superman flies rapidly around the globe to reverse time—from the original ending concept for Superman II, which would have used that particular time-warping power to allow Clark Kent to rewind the clock to a point where Lois Lane had no memory of his Superman secret. Donner and his creative consultant, Tom Mankiewicz, borrowed the ending with the notion that they'd always be able to come back and find a new finale for Superman II when the time came. Then Donner was fired, and Mankiewicz turned down offers to return for the sequel out of loyalty to Donner. This left Lester with half a movie in the can, and a whole lot of work to do.

The lack of an ending for Superman II, coupled with the fact that the film no longer had use of Marlon Brando as Superman's father Jor-El (he was embroiled in a lawsuit with the Salkinds over his earnings and therefore wouldn't appear again), meant that Lester had to largely restructure the film. He brought in screenwriters David and Leslie Newman to work on the new story, which kept the framework of Zod as the villain and Superman's desire to become human so that he could have a relationship with Lois Lane, but changed numerous other elements. He also re-shot numerous scenes that Donner had already filmed to match his own more comedic sensibility.

Ilya Salkind later estimated that Donner had shot as much as 60 percent of Superman II by the time he left the production. By the time Superman II was released, at least that much of the film, or more, was Lester's footage.

7. Superman's mother had a larger role out of necessity.

The casting of Marlon Brando as Jor-El had been a major coup for Superman: The Movie. Though Brando had been expensive, he lent major star power to the production. But after the first film was a hit, the Salkinds saw an opportunity to carry on without him—something Brando didn't help by suing them for more money days after Superman was released. Rather than paying Brando his share of Superman II's profits were he to appear in the film, the Salkinds and Lester retooled the story so that Kal-El would receive messages not from his father, but from his mother Lara. Actress Susannah York was all too happy to return for the sequel, and the Brando footage Donner had previously shot for Superman II was thus scrapped.

8. Superman II's flying harnesses injured more than one actor.

Because Superman II introduced three new Kryptonians to Earth, the crew also had to add three new flying rigs for actors Terence Stamp, Jack O'Halloran, and Sarah Douglas. Though Christopher Reeve ultimately got used to his Superman flying rig, the other actors weren't so lucky. Douglas would later claim that she suffered a shoulder injury due to all the wire work that continued to plague her for the rest of her life, while O'Halloran ruptured a disk in his back, which required surgery. Stamp, for his part, was just forever afraid that the wires holding him up would snap. O'Halloran eventually lobbied for and received better harnesses and safety mats, but the damage was done.

9. Jack O'Halloran and Christopher Reeve almost got into a fight.

Though most of the tension surrounding Superman II was directed at the Salkins and Lester, the cast had their own internal issues. At one point co-star Jack O'Halloran—a former boxer who convincingly played the Kryptonian enforcer Non and had already threatened Spengler over a missing paycheck—stepped up to have a physical confrontation with Reeve over his on-set attitude. It got so heated that O'Halloran pinned Reeve against a wall, forcing Donner (who was still shooting at that point) to intervene and keep his star from being pummeled.

Years later, O'Halloran caused a bit of an internet controversy when he reflected on the confrontation and called Reeve "a bit of an ass" who "believed his own publicity a little bit too much," though he praised Reeve's demeanor and outlook later in his life.

O'Halloran's co-star Sarah Douglas later recalled the incident and backed him up, noting the impact that stardom seemed to have on Reeve at the time.

“I’ve always chosen my words very carefully, because Christopher is, and will remain, the greatest Superman,” she said. “But by the end of filming, I think we all got very tired. I had about nine separate injuries from the flying and various different things and we were pushed very, very hard.

“Chris was less than understanding toward me at the end. He definitely changed in his persona, I think, from the beginning, when he was just a bit of an innocent.”

10. Margot Kidder's anguish at the end was real.

Margot Kidder and Christopher Reeve in Superman II (1980).Warner Home Video

The ending of Superman II is an emotional farewell for Clark Kent and Lois Lane, who've just spent the whole film trying to form a romantic relationship only to find that the world really does need Superman after all, and Superman has to stay a secret. This understanding culminates in a scene in which Lois breaks down, describing her anguish over not being able to have an honest romantic relationship with the man she loves, before Clark gives her a magic kiss that makes her forget the last few days and, therefore, also forget that he's Superman. Margot Kidder's performance in the moment is moving and deeply believable. According to Lester, that's because it was. Kidder was going through major real-life struggles at the time, including the breakdown of her brief marriage to actor John Heard, and Lester did his best to use that reality to play into the scene.

"It was the only time that I've ever been quite so manipulative," Lester later recalled. "We shot that scene, and she was so out of it and so emotionally distraught that it was really a lovely performance."

11. Only one actor promoted SUperman II worldwide.

Superman II was eventually completed amid a variety of tensions between the people who made it. There was tension between the original director and the producers, tensions between the new director and the cast, tension between various co-stars, and more. It was a lot to deal with, which made planning a promotional tour for the film a little difficult, as Warner Bros. feared that stars like Kidder and Reeve might be emboldened to badmouth the makers of the film to a press eager to write about drama. In the end, only one actor was selected to embark on the entire nine-month worldwide promotional journey for the film: Sarah Douglas, who played the Kryptonian Ursa and believed she'd been selected, in part, because she didn't share many of the same on-set experiences and after-hours hotel socializing as her American co-stars.

"It was nine months in the end,” Douglas recalled. “The studio put me through some rigorous tests to see how I would handle situations around the world.”

12. Superman II broke box office records.

Though it was produced in various forms of turmoil, Superman II was a box office smash when it was finally released in the United States in the summer of 1981 (following months of releases in other territories). It set a Friday box office record with $4.5 million on its opening day; topped the all-time best one-day gross the very next day with $5.6 million; then set a record for the best-ever box office week with $24 million, even beating out The Empire Strikes Back, which had been released a year earlier. Superman II ended up being the third highest-grossing film of 1981, behind Raiders of the Lost Ark (the film that eventually toppled its reign atop the box office) and On Golden Pond, which was good enough to cement Lester's return for the Richard Pryor-co-starring Superman III in 1983.

13. There are two very different cuts of Superman II.

Even in the immediate aftermath of Superman II's release, some fans were already arguing over whether or not Donner's version might have been the better film. Over the years, the controversy over Donner's dismissal from the sequel only grew, spurring a certain fervor among fans to cobble together any pieces of his version they could. This was helped along by the Salkinds, who added previously unused Donner footage into Superman II cuts intended for international TV broadcasts. Fans would record this footage, cut it back into the film, and then release bootleg cuts of Superman II highlighting Donner's footage. That, plus robust online discussion of Donner's original plans, was enough to fuel the hope that one day his vision might be restored.

Then, in the early 2000s, two key elements fell into place. First, Warner Bros. planned to release a restored cut of Superman, and as a result went back through all of the footage shot for both films, including much of Donner's previously unseen material. Then, as part of the plan to use Jor-El in 2006's Superman Returns, Warner Bros. cut a deal with Marlon Brando's estate allowing his likeness to once again be used, clearing the way for Donner's deleted Jor-E's scenes to resurface. All that culminated in a call from editor and restorationist Michael Thau, who invited Donner and Mankiewicz to review the old footage and put together a new cut.

Superman II: The Richard Donner Cut was released on home video in November of 2006. Among other key changes, it restores Donner's original beginning and ending plans to the film, adds Jor-El back into the story, and even uses footage originally shot as Kidder and Reeve's screen test for a scene in a Niagara Falls hotel, when Lois Lane fires a gun at Clark Kent to prove that he's Superman.

Additional Sources:
You Will Believe: The Cinematic Saga of Superman (2006)
Superman II: The Richard Donner Cut Commentary by Richard Donner and Tom Mankiewicz (2006)
Superman vs. Hollywood: How Fiendish Producers, Devious Directors, and Warring Writers Grounded an American Icon by Jake Rossen (2008)
Superman: The High-Flying History of America's Most Enduring Hero by Larry Tye (2012)