Last week, Marvel released an incredible new piece of art by Alex Ross, accompanied by four simple words: "GENERATIONS - coming Summer 2017." It is not clear yet whether "Generations" will be a new prestige miniseries, event, or line-wide rebranding a la Marvel NOW, but the name and image highly suggest whatever "Generations" is, it will focus on the idea of legacy heroes in the Marvel Universe.

For decades, legacy heroes have been associated strongly with DC Comics rather than Marvel, and for understandable reasons. Apart from DC's Trinity of Superman, Batman and Wonder Woman, most of its big name superheroes were reimagined into younger, more modern incarnations during the Silver Age. While DC's creators eventually settled on the idea of the multiverse as the in-universe explanation for two radically-different Flashes or Green Lanterns, these stories helped to build an expectation among readers that as characters aged, they might be replaced.

RELATED: Marvel Teases Generations with Epic Alex Ross Art

The DC Universe is full of legacy heroes; there are now enough Green Lanterns to necessitate a whole Corps, nearly as many Flashes, and more Robins (and former Robins) than grains of sand on the beach. While the focus ebbs and flows between the iconic versions and their legacies, the idea of legacy heroes is so engrained in DC Comics that not even the New 52 could kill it.

While legacy heroes have traditionally been more associated with DC, in the past few years Marvel has leaned hard into the concept. Practically every major Marvel hero now has a legacy of one sort or another: Sam Wilson took up the mantle of Captain America, Jane Foster proved she was worthy of wielding Mjolnir, Miles Morales is swinging around New York with Peter Parker's blessing, Kamala Khan has taken Ms. Marvel's battle for justice to Jersey City, and even Nick Fury, Jr., is upping his spy game as an agent of S.H.I.E.L.D. And that's not even getting to Kate Bishop, Sam Alexander, Amadeus Cho, Laura Kinney, Riri Williams, Viv, the Original 5 X-Men, and an unending list of Young Avengers, New X-Men and Spider-Women...

marvel now 2.0

This isn't the first time Marvel has experimented with legacy heroes, though. The publisher has a long history, going back to the very beginning of the Marvel Age of Comics. When Stan Lee and Jack Kirby created "The Fantastic Four," they drew inspiration from one of Timely Comics' Golden Age greats, the Human Torch. But Johnny Storm was an aberration in Silver Age Marvel, as other Golden Age heroes like Captain America and Namor were brought into the then-modern age more or less as they were originally.

Marvel's legacies began in earnest in the 1970s and '80s, as the company became increasingly worried about its intellectual property. Ms. Marvel, Spider-Woman and She-Hulk were all essentially created to claim trademarks, and the Scott Lang Ant-Man and Monica Rambeau Captain Marvel were introduced in part to prevent existing trademarks from lapsing. In the decades since, however, all five have become fan favorites, and by the 2019, two of them will have headlined films in the Marvel Cinematic Universe.

Marvel's most famous legacy of the '70s, though, is without a doubt the All-New, All-Different X-Men. The "X-Men" comic had been survigin on reprints for years, and until "Giant-Sized X-Men" #1, all signs were pointing to its complete cancellation. But with that one issue and its new diverse team of mutants, Marvel revitalized a franchise that would utterly dominate comics for the next two decades.

The next round of Marvel legacies, from roughly the mid-80s to the mid-90s, did not work out quite so well. Rather than creating new heroes based on the concepts of their greatest heroes, Marvel started replacing the heroes themselves. Rhodey took up the Iron Man armor when Tony Stark's alcoholism became too much to bear, Eric Masterson replaced Thor when the latter was banished for "killing" Loki, and Ben Reilly replaced Peter Parker as Spider-Man until they got that whole clone mess figured out (sort of). While each was prominent in their day, only Rhodey, as fellow armored here War Machine, remained an integral part of the Marvel Universe (at least until the recent return of Ben Reilly).

spider-girl-header

The late-90s saw Marvel's last major attempt to introduce legacy heroes: the alternate future of the MC2 (Marvel Comics 2) imprint. The MC2 universe was set roughly 15 years in the future, when most of Marvel's major heroes had retired and been replaced by the next generation, sometimes literally. "Spider-Girl" -- starring Mayday Parker, the daughter of Peter Parker and Mary Jane Osborn-Parker -- was the cornerstone of the line, which also featured books like "A-Next" and "Fantastic Five." "Spider-Girl" was quite successful, lasting for 100 issues, plus another 30 issues of "Amazing Spider-Girl," but the rest of the imprint failed rather quickly, in part because the throwback style did not mesh with the "next generation" theme, and because the alternate universe setting meant many readers thought the stories "didn't count."

What makes the current wave of legacy heroes (almost all of whom have appeared or taken up their mantles since 2010) different is that Marvel has borrowed one of the key elements that has made DC's legacy heroes successful: the idea that multiple versions of a hero can exist at the same time. The return of Steve Rogers didn't mean Sam Wilson had to give up the shield or the title of Captain America, and Jane FosThor regularly fights alongside the Odinson. In most recent cases where Marvel has introduced a legacy hero, they have continued publishing the adventures of the iconic hero.

The effect is that legacy heroes have greatly expanded Marvel's storytelling, by offering iterations on a concept for different audiences. Peter Parker and Miles Morales lend themselves to different types of stories, as do Carol Danvers and Kamala Khan, or any number of legacy pairs.

This isn't just good for today's stories; it's good for the future of Marvel's legacy heroes. If they fit unique niches and do not raise fan ire for replacing beloved favorites, they are much more likely to become permanent fixtures of the universe. A few of this new generation -- Kamala Khan and Kate Bishop in particular -- have already made themselves absolutely essential to the Marvel U. By buying into the idea of next-generational heroes working alongside the people that inspired them, Marvel may have finally solved their legacy problem.

"Generations" is coming Summer 2017.