Before the modern era of superhero blockbuster cinema, two years before 20th Century Fox released X-Men in 2000, Sony Pictures had the opportunity to buy the film rights to Marvel's entirely catalogue of superheroes for just $25 million (£18 million).
The deal has been revealed by Ben Fritz, author of The Big Picture: the Fight for the Future of Movies, due for release in March. He reveals that Sony turned the deal down because they were solely focused on acquiring the rights to Spider-Man.
Sony did acquire those rights, going on to make five Spidey films before reuniting with Marvel for a sixth. In the meantime, Marvel had enjoyed enormous success with its own superhero series.
The original deal put to Sony would have included the X-Men and Fantastic Four - the rights to which went to Fox - as well as Iron Man, Captain America, The Hulk, Thor and other stars of Marvel Studios' Marvel Cinematic Universe (MCU).
The MCU alone has generated $14 billion at the box office. Marvel movies overall have generated around $20 billion, discounting Sony's Spider-Man movies.
Fritz's book reveals that the Sony executive dealing with Marvel was told by fellow executives: "Nobody gives a shit about any of the other Marvel characters. Go back and do a deal for only Spider-Man."
"The mind reels at the lost opportunity," Fritz writes in an extract from the book published by The Wall Street Journal.
"Marvel's 17 releases over the past decade [as part of the MCU] have grossed a total of $13.5 billion [prior to this past weekend's Black Panther] and the studio has remade the movie business.
"Whether you love or hate the seemingly endless parade of big-budget films that seem to exist only to set up sequels and spin-offs, Marvel is the company that developed that model."
While Sony enjoyed enormous success with its first Spider-Man trilogy - directed by Sam Raimi - the subsequent two rebooted films Amazing Spider-Man failed to have the same impact. Plans for its own Spidey Cinematic Universe fell through, so Sony worked a deal to bring the web-slinger into the MCU.
Recasting the role for a third time, Tom Holland became the most youthful Peter Parker yet, and joined the MCU alongside his fellow superhero stars in Captain America: Civil War, before starring in solo outing Spider-Man: Homecoming last year.
Spider-Man is set to appear in Avengers: Infinity War in April and its sequel a year later, before going it alone again in a planned sequel to Homecoming.
Meanwhile Sony is set to release a Spider-Man spin-off based on fan-favourite anti-hero Venom in October and an animated film called Spider-Man: Enter the Spider-Verse, starring multiple characters as the hero, in December.
One of the characters Sony executives thought so little of back in 1998 was Black Panther, whose own solo movie released last week to widespread acclaim and the smashing of box office records. The film is now expected to gross more than many of the Spider-Man films.