Hello and thank you for downloading witness from the BBC World Service with me Mike Lanchin.

Today I'm taking you back to the spring of 1999 when a small team of experts in Milan

completed the mammoth task of restoring

one of the world's most has finally been revealed to the public in Milan after a restoration lasting two decades.

The last supper was painted here 500 years ago for the refectory of Santa Maria de la Gratzier,

but due to his experimental fresco technique, it started to flake away

almost as soon as Leonardo da Vinci had finished it. Now a marathon restoration has attempted to save one of the world's masterpieces from disappearing completely. As a restorer

restorer, I have to say that approaching the genius that was Leonardo was a unique experience.

Something you cannot repeat. It was a great privilege for me. It was not an easy task.

Did you feel satisfied or just exhausted?

I was very tired. I just... or just

needed to get back to normal life again. Pined in Brambia, one of Italy's leading archery stores, spent almost half her professional life working on Leonardo da Vinci's magnificent 4.5 meter high mural

that he'd painted more than 500 years ago on a wall in the convent of Santa Maria de la Gradesie in Milan. For more than 20 years, starting in

1977, she'd led a small team of restorers, painstakingly cleaning, dabbing and

repainting the masterpiece, replacing the fading colours from previous

attempts at restoration.

The state of the painting when I first saw it was unbelievable.

You could not see the original paint.

It was completely covered by plaster and by repainting.

There were five or six layers of paint on top of it.

I had to ask myself whether it was a Leonardo or not because it was totally unrecognizable.

Commissioned by the Duke of Milan, Da Vinci had finished the Last Supper in

...