In Journey into Mystery #83 (Aug 1962), Donald Blake finds a magical walking stick that transforms him into Thor. It’s a rather inauspicious beginning. In that first story, Thor fights stone-skinned aliens, who simply land with only the slightest pretense of explanation.

Thor’s stories would continue in this vein for fourteen full issues, produced at a monthly clip. There’s a nice flourish here and there, but otherwise nothing distinguishes these tales, which were designed to be instantly forgotten and still read like it today. There’s no striving for art here, nor for anything more than childish amusement. And while that’s typical of most of the output of 1960s Marvel Comics, under writer Stan Lee, Thor’s an especially cardboard super-hero, who fights Communists and robots and magicians. His alter ego, doctor Donald Blake, has a typical Marvel love interest of the period named Jane Foster, and their love story gets a lot of space.

In other words, Thor at this early state is about as generic as he could be. His Norse roots consist pretty much of his name, plus a few locales, which are depicted in the sloppiest, most unimaginative way possible. Yes, Loki features prominently, but he’s not from an alien, primitive culture. (Nor is Thor.) Loki’s just another garishly costumed super-villain, who wears an outfit that clowns might be embarrassed to wear. He routinely gets beaten and flies back to a floating city, which could be called absolutely anything at all and not change any of the strip’s meaning in any significant way.

It might be hard to believe, but Thor could easily have been from Mars and those stories would have worked just as well. He occasionally consults with Odin, but he only has the crudest traces of Norse identity (such as a helmet with horns). He could be a soothsayer, or Captain Marvel’s wizard Shazam, or any character’s personal deity / benefactor.

And then we get to Journey into Mystery #97 (Oct 1963). It opens with another forgettable story in which Thor fights Lava Man. We never find out anything interesting about Lava Man. We do see all the newspapers warning of his advance, as if the villain is well-known and his movements being tracked. It’s this kind of nonsense that makes it hard to believe anyone at 1960s Marvel thought anything through at all, nor knew the rudiments of storytelling even at the level of disposable tales intended for children, nor could have possibly held any respect for their audience at all.

The story is at least as preoccupied with the melodramatic soap opera of Blake’s non-relationship with Jane Foster, who winds up leaving as Blake’s employee because he’s not man enough to ask her to marry him. There’s touches of something recognizably human here, but the character’s motivation (not to mention the dynamics of workplace relationships) are twisted so that they resemble nothing but meaningless plot twists and writerly convenience.

And then comes the back-up: the very first “Tales of Asgard” story. Here, Jack Kirby turns loose with his artwork. Gone are the narrow little boxes, clogged with captions and mid-punch dialogue, of 1960s Marvel. Instead, the story opens with a splash page, and most of the pages are four-panel grids. It looks and reads much more like Kirby’s 1970s work (especially New Gods). It certainly doesn’t belong in the same comic as “The Mighty Thor! Battles the Lava Man.”

After the splash page, this first “Tales of Asgard” story opens with an introduction of Norse culture. It’s all generalized and over-the-top, but it’s riveting. Kirby grounds every large panel in a memorable image that attempts to encapsulate some aspect of Norse culture. The story then recounts Norse mythology, through Odin establishing his rule and the World Tree, Yggdrasil.

It’s got an air of having been cribbed from an encyclopedia article, and one must remember that this was a presentation of Norse mythology intended for children. There’s certainly no deep understanding of Norse culture or mythology on display. But damned if these five pages (including the splash page) aren’t by far the most dynamic Thor story to date — and he doesn’t even appear in it!

“Tales of Asgard” was wild. It was filled with energy. It was bursting with crazy Norse ideas, freely reimagined by Jack Kirby’s pen.

It was nothing like the formulaic, boring super-hero melodrama that preceded it. In fact, it like nothing else Marvel or any other mainstream publisher was publishing.

It’s worth noting that the main stories, in this issue and the next three, suffer from especially lackluster artwork. In this issue, Kirby is credited with illustrating the main Thor story, although inker Don Heck is clearing determining the style of the finished art. It looks rather like Kirby provided breakdowns, or less finished art than usual. Beginning with the next issue, Heck would take over as main artist for three full issues, while Kirby would continue the “Tales of Asgard” back-ups. Kirby would soon return, but the contrast between his art and Heck’s only makes these early “Tales of Asgard” stand out more, relative to the main feature.

In #98 (Nov 1963), the front story sees Thor fight… the Human Cobra! Oh, and Jane Foster comes back to Dr. Blake’s employ. You see, having left her employer for not hitting on her assertively enough, she finds her new employer to be a coward — which would presumably invalidate him as a potential suitor, so she goes running back to Blake. Logically.

And then, in the last five pages, we watch what by all rights should be the most boring story: the tale of when Odin (not our comic’s protagonist) defeated the last of the ice giants. Now, ice giants aren’t particularly suited to comics as a visual medium. They’re basically just big white gems. So this story is five page pages of an unknown, Viking-looking protagonist stopping some white gem guys.

Instead, Kirby again focuses on making an impression with every panel. Almost every single panel involves an extreme point of view, some majestic feat that strains the imagination, or both. It’s a visually wild feast, delivered in five pages, and again couldn’t be more different than the by-the-paces story that preceded it.

In the next two issues (#99-100, Dec 1963 – Jan 1964), the main feature has Thor battling a version of Mr. Hyde, from Robert Louis Stevenson’s famous 1886 novel. Not exactly the most imaginative choice.

But in issue #99′s the back-up, Odin battles a fire demon, depicted with Kirby’s wild flair for the dramatic, and imprisons the demon inside the center of the Earth. He even sets the globe, which he’s already protected with Yggdrasil, spinning. In a normal Marvel story, this would all come off as hokey, but here, Kirby’s art feels freed to run wild, and the mythological setting helps the story feel mind-blowing instead of thoughtless — which can at times be a delicate balance.

It isn’t until the fourth “Tales of Asgard” (in #100) that Thor begins to appear — as a boy. It’s almost as if someone finally noticed that Thor wasn’t in the back-up. Thor is sometimes said to be Marvel’s Superman, and Superman’s “early years” as Superboy were still a major and successful part of Superman continuity in the 1960s. But Marvel’s Superboy, in his first appearance, fights giants, throwing a giant pepper shaker at them to make them sneeze — as depicted by Kirby’s wonderful use of dynamic perspective.

The conceit of these early “young Thor” installments of “Tales of Asgard” was that Thor would be rewarded for each good deed. At the end of each five-page back-up, you’d see him lifting his hammer a little higher. But this only sticks around for a couple installments. “Tales of Asgard” was too wild to even stick with its own plan.

Meanwhile, Asgardian elements were gaining prominence in the main stories. Issues #101-102 (Feb-Mar 1964) feature Zarrko, the Tomorrow Man, as their villain. Accordingly, there’s a decent amount of robots and tech. But in #101, there’s a multi-page sequence on the Rainbow Bridge, in which Heimdall blocks Thor. Odin actually gets scenes that Thor’s not in. Even Loki’s suddenly acting a lot more like an Asgardian than a costumed criminal. And even when it’s not depicted, Asgard gets mentioned a lot more. Suddenly, it’s not just a convenient part of this super-hero’s origin story. It’s part of who Thor is.

Issue #103 (Apr 1964) is an Asgard-centered story, with the Enchantress and the Executioner as its villains. The cover not only features them but the Rainbow Bridge. Clearly, the comic’s no longer shying away from this aspect of Thor’s background; it’s now underlining it.

By issue #104 (May 1964), “Tales of Asgard” has basically taken over the main feature. Odin’s scheming behind the scenes; no longer merely occasionally consulted by Thor, he’s now steering the plot and even comes to Earth. The main villains of the issue are none other than the fire demon and a giant, previously seen in “Tales of Asgard.” Heimdall’s there. Balder’s there. The story’s basically Asgard invading the Earth, and nothing like it had ever been done before.

If this sounds like the plot of the first Thor movie, there’s a reason. Issue #104 is the template for all such tales to follow.

In that same issue, “Tales of Asgard” began running stories of other Asgardians, fleshing them out. First up was Heimdall, who guards the Rainbow Bridge.

It’s common for people to claim that characters should always revert to their earliest states, which are somehow seen as purer. Occasionally, continuing characters do emerge onto the page in rich, full forms, from which their stories drift away, requiring correction. But it’s also true that some characters need to evolve; some stories need to find their voice.

The original Thor was a cardboard super-hero, whose Asgardian origins mattered about as much as Krypton or the wizard Shazam, in early Superman or Captain Marvel stories. These were excuses to tell stories about super-powered people. They weren’t important parts of the plot, other than that.

It was “Tales of Asgard” that made Thor an Asgardian, that gave Thor a mythology.

To a large extent, “Tales of Asgard” is the prototypical back-up. Of course, super-hero comics started as anthologies, with tales of different super-heroes. Lots of back-ups feature characters essentially unrelated to the lead feature. Sometimes they star minor characters from the lead feature. But “Tales of Asgard” was another type completely. It was about mining the lead character’s backstory. It gave Asgard the proverbial flesh that made it seem real.

Just as importantly, it gave the comics’ creators an opportunity to think about this backstory and to work their head around it. Perhaps there was a reason those Asgardian elements had previously been handled so sloppily and unimaginatively. Naturally, the new understanding created by the back-ups flowed back into the main strip, reinvigorating it.

That’s what a back-up can do. For them too, “Tales of Asgard” is still the template.