Seventeenth-century Dutch artist Rembrandt Harmenszoon van Rijn is most famous for his paintings and etchings, but he was also a prolific drawer. Approximately 1400 sketches attributed to Rembrandt survive today—and recently, CNN reports, experts identified a new one hiding in plain sight inside a museum in Braunschweig, Germany.

The chalk sketch of a dog was previously thought to be the work of Johann Melchior Roos, a 16th century German Baroque artist known for his paintings of landscapes and animals. The Herzog Anton Ulrich Museum has owned the drawing, called The Braunschweig Terrier, since 1770.

Two years ago, Dr. Thomas Döring, the museum’s curator of prints and drawings, gave the work another look while cataloging works for a digital archive. Thanks to his prior experience studying sketches by Rembrandt and his pupils, Döring was able to detect subtle stylistic details that were unique to the Dutch Master.

The “boldness of the strokes, the variations in the shading from very gentle to quite violent and the expressive gaze [of the dog]—these are very typical idiosyncrasies of Rembrandt's work,” Döring told CNN.

Doring compared The Braunschweig Terrier to the artist’s other known sketches, and asked other Rembrandt experts to weigh in with their opinions. They, too, are convinced that Rembrandt produced the work, the professor told CNN.

Rembrandt practiced his artistic technique by sketching animal studies in chalk. He rarely made preparatory sketches for his paintings, but experts at the Herzog Anton Ulrich Museum have compared his terrier drawing to the barking dog crouching in the corner of the artist’s famous 1642 painting, The Night Watch.

The newly-labeled drawing is slated to go back on display this April, as part of a new exhibition at the Herzog Anton Ulrich Museum.

[h/t CNN]