Painted by one of the world's most famous street artists, installed first at a mud-soaked music festival and then beneath an oak tree, the trailer was home first to an itinerant British couple and then their growing family.
In 1998, the truck owner knew Banksy as someone he had once busked with in Bristol, England, and the friend of his sister's boyfriend, and for 200 pounds (about $300 at the time), he agreed to turn his trailer into a blank canvas for the Glastonbury music festival.
Recently pried off the trailer, the work called "Silent Majority," which depicts a commando raid to install sound gear for a rave, goes up for auction Monday in Paris.
The Digard auction house hopes it will fetch at least $400,000. Failing that, the plan is to put it up for private sale.
The owner wanted only his first name, Nathan, to be used to avoid more hassle over his strange and valuable possession. His four children, who tagged along to Paris, still treat the work casually, slipping up alongside it on the street where it was displayed for the weekend.
Nathan had already been on the road for most of his life when Banksy approached him about the trailer that was his home at the time. In exchange for a bit of money and some tickets to the music festival, the then-obscure artist had a deal. He and a collaborator known as Inkie set to work, painting during the annual festival best remembered that year for its ankle-deep mud.
"I took some Champagne to sell, so we were drinking and selling Champagne while he was painting," Nathan said. "Other than that, our lives just carried on. Then he got famous and it got valuable."
Bansky himself is as elusive as his work is public. The Internet is full of speculation about his identity, fuelled by Banksy's refusal to play along. His website, displaying a photo of a man in a balaclava, says he "is not represented by an art gallery, is not on Facebook and has never used Twitter."
Nathan said wistfully he hadn't seen him in years: "He's hidden himself away from us lot for some reason."
Inkie is also attending the Paris auction, where he was given a blank canvas and space on the sidewalk in a ritzy Parisian version of the mud-splattered Glastonbury day when he and Banksy painted the trailer. "We painted it live over a day," Inkie said after carefully peeling off a latex glove and offering a handshake. "He came up with the idea."
The trailer made its way to other festivals over the years, with Nathan driving and setting up tents as he had in the years before the spray paint hit his home. And it started to get more attention.
"Silent Majority" was painted freehand, rather than using stencils as has been Banksy's signature, and is a rare example of the artist's early work, said Mary McCarthy, a British street art expert who helped organize Monday's auction.
"This piece was a commissioned piece. So it wasn't a piece that Banksy just threw on the side of a truck or threw on a wall," McCarthy said. Nathan doesn't quite describe himself as a commissioner of artwork, but the piece became part of his life over more than a decade, after he met his wife and the two of them started a family.
"If I didn't like it, I would have painted over it," he said. "Then when he finished it, it looked great. You walk out your truck in the morning, open the door and there's 50 people taking photos."
Nathan said he hopes to build a house with the money from the proceeds, putting it on the same piece of land where the trailer stood for so long.
"We'll end up living in it again," he said. "It needs a different type of owner."
Banksy himself won't be at the auction, but the organization that he set up to authenticate his work has given "Silent Majority" a rare certificate that allows its buyer the unusual chance to own the piece legally. On his website, Banksy discussed the sale of street art.
"As a kid I always dreamt of growing up to be a character in Robin Hood," he wrote. "I just never realized I'd end up playing one of the gold coins."