LONDON (AFP) ― A landmark exhibition of paintings by Leonardo Da Vinci goes on show at London’s National Gallery on Wednesday, the first time so many of his masterpieces have been displayed together.

Among the nine paintings are his two versions of the “Virgin of the Rocks,” which will hang face to face for the first time.

Da Vinci is thought to have produced about 20 paintings during his lifetime, but just 15 have survived.

Art fans will also be able to see “Salvator Mundi”, which was only recently authenticated as a Da Vinci, as well as three groundbreaking portraits: “The Portrait of a Musician”, “La Belle Ferronniere” and “The Lady with an Ermine.”

The exhibition, which also includes more than 50 drawings, focuses on Da Vinci’s observation, imagination and painting technique which developed while he was employed as the court painter in Milan in the 1480s and 1490s.

“Madonna of the Yarnwinder,” “Saint Jerome” and “Virgin and Child” (“Madonna Litta”) make up the nine paintings, which are complemented by a full-scale contemporary copy of “The Last Supper” mural in Milan, shown in a room nearby.

“The exhibition focuses for the very first time on Leonardo the painter, and we’ve been able to gather here the largest number of pictures that’s ever been seen in one place,” said curator Luke Syson.

“What we see here is an extraordinary journey, one that takes Leonardo from an artist who believed that his responsibility was to record nature as precisely as possible, to an artist who believed that his creative skills were akin to those of God himself.”

Most of the paintings have been loaned from European museums, a remarkable achievement for the National Gallery because curators are normally deeply reluctant to allow their Da Vinci treasures to be shown elsewhere.

The result is still an extraordinary collection that is set to pull in the crowds ― a gallery spokeswoman confirmed that it had sold an “unprecedented number” of advance tickets to the show, which runs until Feb. 5, 2012.

Five hundred tickets will be held back for sale each day, but to avoid any overcrowding, the gallery has limited the numbers of visitors to 180 every 30 minutes, down from the usual 230.

In a world first, a special opening night on Tuesday will be broadcast live to 40 cinemas across Britain.

The main highlight is the two versions of the “Virgin on the Rocks,” which were commissioned at the beginning and the end of Da Vinci’s time in Milan.

The first one is held in the Louvre in Paris, and the second at the National Gallery, where it has recently been restored to reveal clearly one of the artist’s trademarks ― his astonishing inability to finish his paintings.

“When you look closely you’ll see some parts of the picture are barely taken beyond the initial underdrawing and modeling stage, for example the hand of the angel that supports that back of the Christ child,” said the gallery’s director of conservation, Larry Keith.

He added: “All those things are indicative of a work still in many respects in progress, somehow provisional, and that is quite characteristic of Leonardo in the way he worked.”

Da Vinci’s revolutionary portraits are another highlight, particularly the painting of Cecilia Gallerani, his patron Ludovico Maria Sforza’s mistress.

“The Lady with an Ermine”, which was stolen by the Nazis from Poland before being returned and displayed in Krakow, is proclaimed as the first truly modern portrait for the way it appears to convey Gallerani’s inner thoughts.

The painting, as well as the portraits of the male musician and “Belle Ferronniere”, show Da Vinci “really revolutionizing the genre, giving his sitters an interior life which had never been seen before”, Syson said.

The best-known of Leonardo’s works, the “Mona Lisa,” will however be staying in Paris.