An in-depth study of Leonardo da Vinci's earliest-known drawing has proved that the great Renaissance artist was ambidextrous, Italy's Uffizi Gallery said on Monday.

The scientific and technological analysis also revealed a hidden, previously unknown landscape sketch, also by Leonardo, on the back of the original work.

"It is a real revolution in the field of Leonardo studies," said Uffizi director, Eike Schmidt.

The findings were announced a month ahead of the 500th anniversary of the death of Leonardo, with museums around Europe organising exhibitions and events to celebrate the life of the man responsible for such masterpieces as Mona Lisa.

His first-known drawing is dated Aug. 5, 1473, when Leonardo was 21, and shows a landscape of the Arno river valley and Montelupo Castle, just outside Florence.