The world’s second-known portrait of Leonardo da Vinci has been unearthed. For years, the Old Master drawing of an unknown bearded man has belonged to the British Royal Family. The identity of the sitter was unknown until the head of prints and drawings of the Royal Collection took a closer look. The telltale clues to the elderly man’s true identity included his “luxuriant” but unfashionable facial hair and the shape of his nose.

The three-quarter profile of a bearded man is believed to have been made by an assistant to Leonardo shortly before the artist’s death in 1519. The casual depiction is on a piece of paper that also has a sketch of a horse leg on it, part of a group of studies made for an equestrian monument that the King of France commissioned Leonardo to create.

The drawing will go on display later this month as a part of the exhibition “Leonardo da Vinci: A Life in Drawing,” which opens May 24 at the Queen’s Gallery at Buckingham Palace. The show is one of the headliners in a year of celebrations going on Europe-wide to commemorate the 500th anniversary of the Renaissance man’s death.

A sketch of Leonardo, the head of a youth, and a horse’s legs, and A portrait of Leonardo, attributed to Francesco Melzi, in the Print Room, Windsor Castle. Royal Collection Trust. © Her Majesty Queen Elizabeth II 2019.

The drawing was first noticed by Martin Clayton, head of prints and drawings at the Royal Collection Trust, when he was preparing works from Windsor Castle for the show of around 200 works.

Clayton says that the features of the portrait bear strong similarities to the only other known drawing of Leonardo, one by Italian painter Francesco Melzi. “Leonardo was renowned for his well-kept and luxuriant beard at a time when relatively few men were bearded—though the beard was rapidly coming into fashion at this time,” says Clayton.

His “elegant straight nose,” beard shape, and “a ringlet falling from the mustache at the corner of the mouth and long wavy hair” were among the attributes of the image that tipped Clayton off.

Leonardo would have been around the age of 65 at the time he the portrait was made. Clayton noted in a statement that the artist “appears a little melancholy and world-weary.”

“Leonardo da Vinci: A Life in Drawing” will be on view at The Queen’s Gallery, Buckingham Palace, London from May 24 through 13 October 13, 2019.