MILAN (AP) — In honor of the Milan Cortina Olympics, Milan cultural officials are for a brief time only allowing visitors access to a long-hidden wall and ceiling painting by Leonardo da Vinci while restoration work is underway.

The vast painting of a pergola covered with intertwined flowering branches inside Milan’s Sforza Castle is concealed behind a six-meter (nearly 20-foot) towering scaffolding in the Sala delle Asse. Letters establish that Leonardo started the work, but it’s one he left unfinished.

“In 1498, he had to flee because the French arrived in Milan, and after that date it was covered over, hidden,” said Luca Tosi, heritage curator at Milan’s landmark Sforza Castle, which is in the same Sempione Park where the Olympic flame will burn during the Feb. 6-22 Winter Games. In another sign of Leonardo’s impact on Milan, the Olympic cauldron itself is inspired by the Renaissance genius’ geometric studies, officials announced this week.

Under the French, the castle became a military barracks and the painting, which covers the ceiling and part of the wall, was covered with plaster. The work was only rediscovered early last century, when restorers removed the plaster and filled in color to match Leonardo’s work.

“As a result, Leonardo scholars no longer recognized them as a true Leonardo, but rather as a repainted Leonardo, somewhat a fake, to use a popular term,” Tosi added.

Visitors will be able to climb up the scaffolding and view the restorers at work during a brief window from Feb. 7-March 14, after which it will be closed to the public again for another 18 months to complete the work.

Restorers are using Japanese rice paper with demineralized water to remove salts that have seeped into the walls, gradually cleaning the surface of the painting.

“The hardest part is that Leonardo’s painting is very delicate, there are some liftings, there are more fragile parts and therefore the work must be done centimeter by centimeter, with the utmost attention and care,” Tosi said.

The painting is a study of leaves and plant species that provides yet more evidence of Leonardo’s infamous scientific inquiry, said Tomasso Sacchi, Milan’s top culture official.

“It’s a thrill to know another Leonardo and to experience this extraordinary dedication to various forms of knowledge by this fundamental figure in our history,” Sacchi said.