Sometimes it's difficult to fathom that Black Widow's only been a part (and sometimes even the best part) of the Marvel Cinematic Universe since 2010 -- it feels like we've all been desperately hoping and campaigning for a Black Widow-led movie since life first trudged out of the primordial ooze and developed rational thinking skills.

If it seems like Marvel's been dancing around the idea of a film featuring their most adept assassin for years, it's because they have, literally. And yet, these days it's starting to look like we'll have to wait until at least 2020 (that'll be TEN YEARS of Black Widow, mind you) to see Scarlett Johansson rock the house as a Marvel movie's featured protagonist. Here's a comprehensive history of every time somebody's dangled a live-action Natasha Romanoff in front of us, starting with the earliest known example of a Black Widow project falling flat -- which occurred long before you probably think it did.

1975: The Daredevil/Black Widow TV Series

A long time ago, Angela Bowie -- yep, the then-wife of singer/songwriter David Bowie -- tried to get a TV series featuring Daredevil and Black Widow (who were at that point romantically involved in the comics) off the ground. She and actor Ben Carruthers only got as far as the above costume tests, and were unable to get the series made because it was deemed "too difficult and expensive to film," as she told Kuljit Mithra of Man Without Fear.

2004: Lionsgate Turns Down The First Ever Black Widow Script

The rights to the Black Widow character were sold off in the '90s, and in 2004 "X-Men" and "X-Men 2" writer David Hayter penned a script for Lionsgate, which closely followed the comic book origins of Natasha Romanova as she's adopted by Ivan Petrovich, trained in the Red Room with other child assassins, undergoes a medical procedure that gives her superpowers, and defects from Russia. Lionsgate, however, passed on the film, citing other female-led action movies that had recently performed poorly at the box office.

“A number of female vigilante movies came out,” Hayter told Comic Book Resources back in 2011. “We had 'Tomb Raider' and 'Kill Bill,' which were the ones that worked, but then we had 'BloodRayne' and 'Ultraviolet' and 'Aeon Flux.' 'Aeon Flux' didn’t open well, and three days after it opened, the studio said, ‘We don’t think it’s time to do this movie.’ I accepted their logic in terms of the saturation of the marketplace, but it was pretty painful.”

May 4, 2010: "Iron Man 2" Is Released

Not long after Lionsgate turned down Hayter's script, Marvel regained the movie rights to Black Widow, and included her in the "Iron Man" sequel as a S.H.I.E.L.D. agent working undercover as Tony Stark's assistant.

2010/2011: Nicole Perlman Writes Black Widow Treatment

Nothing came of the treatment, which was written by Perlman as part of the Marvel Writers Internship program, and which wasn't discovered by fans until much later. But it definitely exists in a Disney vault somewhere.

September 2010: The First Offical Movie Whispers

Black Widow hype didn't start to hit a groundswell until after "The Avengers" came out, but according to Marvel Studios president Kevin Feige, they'd certainly already been thinking about it. In a press conference for the "Iron Man 2" blu-ray/DVD release, he told reporters, “We’ve already started discussions with Scarlett about the idea of a solo movie and have begun putting together concepts, but ‘The Avengers’ comes first.”

December 2011: ScarJo Gets On Board

In an interview with SuperHeroHype, Johansson said, "I love playing the Widow. I think she’s got a very interesting past, a lot of storylines to explore, and certainly Kevin (Feige) loves that character. I think that Marvel has a very personal relationship with their fans, and I think if the fans want [a solo film], and the audience wants it, nothing’s impossible. I would love to explore that option as well. Like I said, I love the character and it would be nice to see something nice and gritty.”

May 4, 2012: "The Avengers" Opens, Makes all The Money

AND IT WAS AWESOME. No more so than when Natasha Romanoff was on screen, as she was one of the most important characters in the film.

May 2012: ScarJo Continues To Address Solo Film

Once "The Avengers" came out, fans immediately began clamoring for Natasha to lead her own film -- and Scarlett Johansson was happy to entertain the idea.

"I love her origin story. I think it's just such a riveting one," she told The Huffington Post right as "The Avengers" was being released in theaters. "It's just steeped in history and the richness to shoot in Russia, perhaps. ... I hope that the fans' voice is loud enough and they want to see a Widow origin story, I know Marvel would be happy to entertain that. We've spoken a lot about it."

June 2013: Joss Whedon Discusses The Lack Of Female Superheroes

Whedon, who was famously attached to a Wonder Woman script in 2007 before the project was abandoned, told The Daily Beast that he was pissed about the lack of female superheroes in film.

"Toymakers will tell you they won’t sell enough, and movie people will point to the two terrible superheroine movies that were made and say, You see? It can’t be done. It’s stupid, and I’m hoping 'The Hunger Games' will lead to a paradigm shift. It’s frustrating to me that I don’t see anybody developing one of these movies. It actually pisses me off. My daughter watched 'The Avengers' and was like, ‘My favorite characters were the Black Widow and Maria Hill,’ and I thought, Yeah, of course they were. I read a beautiful thing Junot Diaz wrote: ‘If you want to make a human being into a monster, deny them, at the cultural level, any reflection of themselves.’”

June 2013: Feige Teases Possible S.H.I.E.L.D. Spin-Off

Just after "Marvel's Agents Of S.H.I.E.L.D" was announced as a TV series in April 2013, Feige spoke with The Playlist about the possibility of a movie featuring the otherS.H.I.E.L.D. characters from "The Avengers."

"There's no definitive plans, but we have started talking and talking with Scarlett about what a Widow movie could be," Feige said. "Internally we've also started thinking what a 'Hawkeye' movie could be, how we could continue to explore the organization S.H.I.E.L.D, which has a pretty big part in 'Thor,' smaller parts in the two 'Iron Man' films and has a giant part in 'The Avengers.' [So it's like], what would a stand-alone "S.H.I.E.L.D." be like? It all goes back to the comics. Sometimes the answer is -- when looking at a certain run of issues -- 'no way' and sometimes the answer is 'maybe, let's continue to explore it' and certainly with Hawkeye and Black Widow those are two that we're exploring."

October 2013: No Female-Led Movies Until 2017

Speaking with Movies.com, Feige noted the importance of the MCU's female characters.

“I know we have numerous exciting female heroes, whether none of them are currently slated, some of them are in development — frankly, you can look at what Jane Foster does in ['Thor: The Dark World'], look at Pepper Potts literally saving the day and defeating the bad guy in

'Iron Man 3,' and I’d say we already have great female heroes that are showcased and play major roles in our universe now. 'Captain America: The Winter Soldier,' as you will see, features Black Widow in her biggest role yet in any of our films. In terms of a solo standalone female hero, I’m not sure when that will be. We make two movies a year, we’ve planned through 2015 and we have some ideas of what we’re doing in 2016 and 2017, so we’ll see what happens.”

November 2013: Thor and Loki Want a Black Widow Movie

When asked what female-led solo film they'd like to see make it to the MCU, Chris Hemsworth and Tom Hiddleston made their allegience to their "Avengers" co-star perfectly clear. “I’d live to see a Black Widow movie… I think it will [happen]," Hemsworth said. "It has to. We’ll rally for it. We’ll get it started…”

“That would be amazing,” Hiddleston added. “Scarlett would really bring the thunder on that.”

February 2014: Black Widow Film "In Development"

Just before "Captain America: The Winter Soldier" was released, Feige spoke with Total Film Magazine about the possibility of a solo-led Black Widow film, while teasing her expanded plotline in "Avengers: Age of Ultron."

"We start filming the next 'Avengers' film at the end of March," he said. "[Black] Widow's part in that is very big. We learn more about her past and learn more about where she came from and how she became in that film. The notion of exploring that even further in her own film would be great, and we have some development work with that."

March 2014: Scarlett Still Wants A Black Widow Movie

"If you want to see a Black Widow spin-off movie, then I want to see it," Scarlett Johansson told reporters on the red carpet of the "Winter Soldier" London Premiere. "We'll see. We will put the request into Marvel tomorrow."

April 2, 2014: "Captain America: The Winter Soldier" Opens

Black Widow has an incredibly important, expanded role in helping Steve Rogers discover the origins of the Winter Soldier and stopping HYDRA from achieving their nefarious goals. Really, you could argue that she co-stars alongside Chris Evans.

April 2014: Scarlett Says It's Up To The Fans

"You know, there’s always the possibility in this kind of Marvel madness that, you know, anything could happen," Johansson told Screen Rant on the possibility of a spin-off. "So if the audience wants something like that and we could really, you know, carve out a great story for her that’s a continuation of what we already know, then I’d be totally for it."

August 2014: Nicole Perlman's "Black Widow" Treatment Revealed

Just after the success of "Guardians of the Galaxy," writer Nicole Perlman took to Twitter to address rumors of her mysterious Black Widow treatment.

"I wrote a treatment for Black Widow in 2010/2011, but I am not actively developing it right now," she said. "Also I can't speak for how long it will be until we get a Black Widow movie. I hope soon, but I know that Marvel has a lot on their plates."

August 2014: Neil Marshall Would Love To Direct

"I would love to do a Black Widow movie," the "Game of Thrones" director told Vanity Fair. "That’s perfect, I would love to do that. That character is really interesting, she doesn’t have any superpowers, she just has extraordinary skills, and the world that she comes from, being this ex-K.G.B. assassin, I find that really fascinating, yeah."

August 2014: Even Jessica Chastain Wants a Black Widow Movie

“Where is the Scarlett Johansson superhero movie? I don’t understand it, why is it taking so long for this?” Chastain asked The Wrap. “This woman clearly shows that people want to go see her in the movies. 'Lucy,' didn’t it beat 'Hercules' by a lot opening weekend, when it was made for a lot less? She shows that she kicks ass, she’s a great actress. 'Under the Skin' is an incredible film, and why are we still waiting for a go-ahead on a superhero movie starring Scarlett Johansson?

“To me, it’s a no-brainer,” she added. “You want to make money, put Scarlett Johansson in a superhero movie!”

September 2014: Robert Downey Jr. Weighs In

"Doesn’t Scarlett deserve a break?” RDJ told USA Today at the Toronto Film Festival, noting that Johansson had just recently become a mom. He also acknowledged the importance of Marvel's female characters, saying, "The 'Iron Man' franchise would never have taken off without [Gwyneth] Paltrow. There’s something about her that grounded the story. She’s not your typical lady in a superhero movie, and then by 'Iron Man 3' she’s swallowing serums and putting on suits and kicking [butt] and all that stuff.”

But, he added, “it would be kind of more appropriate for a character that already was like a Black Widow [to lead a movie]. It just seems like whatever Scarlett does people want to go see it.”

October 2014: Marvel Exec Victoria Alonso Throws Her Hat In

When asked by Variety when we can expect a 'Black Widow' solo film, Executive Producer Alonso noted, "If it were up to me, it would be today,” adding that the recently announced "Wonder Woman" movie from DC didn't do anything to change Marvel's collective mind. “We have so much pressure internally for everything we do, we don’t need outside pressure. We are always so hard on ourselves.”

October 2014: Black Widow Movie Fan Campaign Gains Serious Traction

Led by the Tumblr "Where Is My Black Widow Movie?," fans of the master assassin began to organize, and planned to inundate social media with the hashtag #BlackWidowMovie on November 2 of that year.

October 28, 2014: Phase 3 Officially Announced

While the newest set of expected Marvel movies included the first female-led film in "Captain Marvel" and the first POC-led film in "Black Panther," a solo Black Widow film was nowhere to be found.

November 2014: "Black Widow" Comic Writer Teases Script Treatment

After the #BlackWidowMovie campaign took hold, Nathan Edmonson joined in the fun by putting together a short treatment for a possible solo film. It's since disappeared from his Twitter and website, but you can still find a brief excerpt on The Mary Sue.

November 2014: Clark Gregg Wants More Natasha In His Life

At least, according to this Q+A he did on his Facebook page.

January 2015: Hayley Atwell Wants to Be In a Black Widow Movie

Black Widow fans were delighted when "Marvel's Agent Carter" began poking around in the Soviet Union only to discover the 1940s beginnings of the Red Room program that spawned our girl Natasha -- and now Peggy herself thinks that's a connection worth exploring.

"If there was a Black Widow film I'd love to be part of that." she told ComicBook.Com. "I think that a lot more females on screen together is a very powerful dynamic. I think that would be great fun to see her up against other women."

April 2015: Joss Whedon Thinks Black Widow Is Due For A Movie

When MTV News asked Joss Whedon who in the Avengers he'd like to see get their own movie, his answer was not surprising. “Solo? Anybody solo? Well, you know… Ultimately, I think the Widow is due.”

Johansson agreed, speaking to Entertainment Tonight at the same World Premiere event. “From his lips to Marvel’s ears, I guess,” she said. “I’ll do it if he’ll direct it.”

April 2015: Black Widow's "Contract Has Mutated"

At the "Age of Ultron" press day earlier this month, Scarlett Johansson spoke with Collider about her feelings on a Black Widow Movie.

“I think that there’s room for a standalone movie," she said. "The character has a really rich origin story and I’ve been really fortunate to kind of place all these layers on top of one another and kind of build up this character to this point where I think I can now start to peel them away and reveal different sides of her and really focus on—I think I’ve been able to grow with the character, the character’s been able to grow with me."

Johansson also noted that she and Feige have talked about the idea and "share a similar vision" for a possible standalone series, and that her role has already expanded far beyond what Marvel expected for Black Widow. "For instance, I wasn’t contracted into doing 'Cap' movies, but that storyline worked out so well I kind of branched off and I found myself in that standalone movie. My contract is kind of mutating, I guess [laughs] or morphed to fit the demand of the character."

April 2015: Mark Ruffalo Believes In The Black Widow Movie

ScarJo told Access Hollywood that the Black Widow movie is "just a rumor", but Ruffalo refuses to believe that it's not totally happening. Bless his giant heart.

April 2015: But Ruffalo's Not Kidding, Though

While taking over for the E! Online Instagram, the Hulk actor -- who's always been an advocate for feminism and representation in the media -- snapped a pic of a "Where Is My Black Widow Movie?" fan and shared her sentiment with an "Um, yeah!"

Watch Scarlett Johansson put on the suit again for "Avengers: Age of Ultron" when it hits theaters on May 1... But not in a "Black Widow" movie. At least, not yet.