You never know what you’ll find hidden in a Maine attic: lobster traps, weathered Stephen King novels, perhaps a long-lost Rembrandt. The latter is what turned up in an estate in Camden, and it’s now in the hands of a European collector, who scooped it up at auction late last month for $1.4 million, reports the AP. Per a release from Thomaston Place Auction Galleries, company owner Kaja Veilleux was making a “typical house call” at the farmhouse when, “among a collection of heirlooms and antiques, tucked away in the attic,” Veilleux spotted the 17th-century Portrait of a Girl, “a stunning portrait of a teenage girl, her serene expression framed by a ruffled white collar and cap.”

Veilleux tells the New York Times that he knew “right away” he was looking at a Rembrandt, painted on an oak panel and mounted in a handcarved gold frame. A label on the back of the unsigned painting confirmed it was a Rembrandt and also noted it had been on display in 1970 at the Philadelphia Museum of Art, though a museum rep tells the Times that the exhibition of the piece was so long ago that there are no records of it. Apparently, other than its brief stint there, the artwork had remained in the hands of a family since the 1920s, though those owners haven’t been identified.

The painting’s new owner is also anonymous, outbidding eight others and getting what appears to be a bargain in the deal, as the painting they bought for $1.4 million on Aug. 24 hasn’t even been authenticated yet. “The value of this painting is probably in the area of $15 million,” authentication expert Mark Winter tells the Times. Still, the sale is the auction house’s biggest fetch ever. “Out of all the phone bids I’ve handled, I never imagined I’d help close a deal for over a million dollars,” says Zebulon Casperson, who repped the winning bidder, per the release. “It feels like a shared victory.” No one knows how or why the painting ended up stashed in the estate’s attic. (More Rembrandt stories.)