The Sword in the Stone dragged “King Arthur” down.

Despite costing $175 million to make and tens of millions more to market, “King Arthur: Legend of the Sword” was a massive disappointment in cinemas this past weekend. Directed by Guy Ritchie and starring Charlie Hunnam (“Sons of Anarchy”) and Jude Law, the Warner Bros movie only took in $15.4 million for its opening weekend at the North American box office. It fared little better internationally, drawing in a paltry $29.1 million for overseas markets.

“The concept missed, we’re very disappointed,” Warner Bros’ domestic distribution chief Jeff Goldstein told the Hollywood Reporter. By some estimates, this is the biggest film industry flop since this January’s “Monster Trucks,” which made just a little over half its $125 million budget.

In some ways, the quest for Excalibur was doomed before it even opened. Fans were decidedly unimpressed when preview footage was screened at last year’s Comic-Con, leading Warner Bros. to postpone its release so that “King Arthur” could be improved. “Whatever comes out of Comic-Con can follow a movie forever,” says Paul Dergarabedian, senior media analyst at comScore. “It is a crucible of fan sentiment and has a lot of clout.”

Critics also hated the film. According to Rotten Tomatoes, less than 20% of top film reviewers liked “King Arthur.” In a review representative of the mood, the Wall Street Journal called it “vacant, joyless, incoherent, screw-loose and idiotic…a stinker for the ages.”

Opening a film on the second weekend of May–on which Mother’s Day is celebrated–poses additional challenging. A Disney/Marvel blockbuster has traditionally dominated the date, as “Guardians of the Galaxy 2” did this year and “Captain America” in 2016. But “King Arthur” didn’t even make it into second place thanks to “Snatched,” a comedy starring Goldie Hawn and Amy Schumer as a mother-and-daughter duo going on an adventure together.

More crucially, young people really didn’t bother with “King Arthur.” 68% of the movie’s audience was older than 25, according to comScore PostTrack data. Meanwhile, over half of those who watched “Guardians of the Galaxy 2” this past weekend were younger than 25. That’s not entirely a surprise. With the notable exception of “Gladiator,” medieval-themed live action movies tend to bomb with the young.

“For a summer PG-13 movie, you really want a nice portion of the teenage crowd,” says Dergarabedian. “Women really like Charlie Hunnam and he has huge appeal to the female audience, but it’s really hard to get teens to watch a movie like this.”