Treasure trove, from Cezanne to Toulouse-Lautrec, expected to raise total of pounds 50m at auction

One of the world's most important art collections is up for sale. The substantial Loeb collection includes a portrait by Cezanne which is expected to fetch a record price of more than pounds 17.9m.

The collection, to be auctioned at Christie's in New York on 12 May, will also include masterpieces by Manet and Toulouse-Lautrec and is expected to raise a total of pounds 50m.

The star work is Cezanne's portrait Madame Cezanne au fauteuil jaune. It is the only one of a series of four paintings of the artist's wife seated in a yellow armchair still to be held in private hands and has been described as one of the most extraordinary works of modern painting.

The other three are in the collections of the New York Metropolitan Museum of Art, the Art Institute of Chicago, and the Museu de Arte in Sao Paolo, Brazil. The same artist's Rooftops of L'Estaque, which dates from 1883- 85, is predicted to fetch up to pounds 6.25m.

Toulouse-Lautrec's Seated Dancer with Pink Stockings, from around 1890, which depicts a scene from the painter's beloved Montmartre cabaret demi- monde, is also for sale and estimated to fetch between pounds 5m to pounds 6.25m.

There is also one of only two known self-portraits by Edouard Manet, painted towards the end of his life in about 1878 and depicting him as a successful modern gentleman.

John and Frances Loeb, both now dead, were well known philanthropists in American society.

Their donations to favoured causes totalled pounds 160m and included a pounds 45m gift to Harvard University, Mr Loeb's alma mater.

The Loebs donated Van Gogh's Oleandres and Picasso's Arlequin accoude" and La femme en vert to the Metropolitan Museum of Art.

They also donated Boulevard Montmatre, Printemps, by Pissarro, to the Israel Museum.

Mr Loeb was the son of a German immigrant who worked his way up to become a wealthy banker and a pillar of Wall Street's financial clique. Described as one of Wall Street's "old guard", he was head of the prestigious brokerage house Loeb, Rhoades and Company. Under his reign, it became one of the most respected and powerful firms on Wall Street. He was also a long-serving governor of the New York Stock Exchange.

Mrs Loeb was New York City's commissioner to the United Nations for 12 years in the 1960s and 1970s.

They bought most of their art works in an intensive spell of purchasing during the 1950s and 1960s which confirmed their reputation as being among the world's most distinguished art connoisseurs.

The couple turned their home into a virtual museum of art, full of remarkable works from the 19th century and earlier. Their's is one of the world's most important private collections of Impressionist and Post-Impressionist art.

Christie's chairman, Christopher Burge, said: "We are very proud and honoured to have been entrusted with the sale of this exceptional collection of Impressionist and Post-Impressionist art, which was assembled with passion and a discerning eye by collectors whose names are well known and respected throughout the world."

The sale also provides the first opportunity in decades for the paintings to be viewed by the general public, in a travelling exhibition which will visit Singapore, Japan, France and Switzerland.

Proceeds from the auction will go towards the foundation of a philanthropic fund to support programmes in education, health, family planning and art.

Christie's figures, page 22