Swiss art trader Ernst Beyeler, who became renowned for one of the most impressive international collections of 20th century art, has died at the age of 88, his foundation said.

" He died quietly in his sleep at his residence in Riehen," on the outskirts of the northern city of Basel, the Beyeler Fondation said in a statement.

After his first exhibition of Japanese woodcuts in 1947, some 16,000 works of art including those by some of the biggest names in modern art passed through Mr Beyeler's hands over 50 years.

His reputation and friendships with famous painters were such that Pablo Picasso allowed him to pick 26 of his works during a visit to the ebullient artist's studio at Mougins in southern France in 1966, according to the foundation.

An economist and salesman by training, Mr Beyeler nurtured his passion for art during the 1940s in an antique bookshopowned by a German Jewish refugee in his native Basel.

After the death of the owner, Mr Beyeler took over the business and gradually turned it into a gallery with his wife Hildy. He often said he was guided by little more than his own intuition rather than by fashion or trends.

His breakthrough came in the early 1960s with the acquisition of about 340 works by Cezanne, Paul Klee, Monet, Picasso, Matisse, Leger, Mondrian and Braque from the Thompson collection in the US.

The Beyelers established their foundation in 1982, but the collection was only shown in its entirety for the first time in Madrid seven years later.