The French businessman Pierre Bergé, who helped his partner Yves Saint Laurent build his fashion house into a worldwide brand, has died at his home in the south of France.
The 86-year-old had suffered a long illness, said the foundation the two men set up.
Saint Laurent and Bergé together established the Yves Saint Laurent label in 1961.
Bergé was also a patron of the arts both in France and Morocco.
He was a passionate campaigner for gay rights and founded Sidaction, a fundraising organisation dedicated to Aids research and treatment, in 1994.
He died on Friday at his home in Saint-Rémy-de-Provence.
Former French culture minister Jack Lang said he was a “true prince of the arts and culture”.
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Bergé was an ambitious provincial who came to Paris after World War Two and found his new home among the city’s arts and fashion elites.
On his first day in Paris in 1948, he was walking along the Champs-Elysées when the poet Jacques Prevert fell out of an apartment window and landed on him.
In his early years in the city, Bergé became the lover of the artist Bernard Buffet and was friends with Albert Camus and Jean Cocteau.
But it was his encounter in 1958 with young designer Yves Saint Laurent that changed his life, says the BBC’s Paris correspondent Hugh Schofield.
He separated from Saint Laurent in 1976, but they remained business partners and friends for their whole lives.
The sale of the fashion house in the 1990s made them both immensely wealthy.
Saint Laurent died from brain cancer in 2008.
Bergé had been due to inaugurate two museums dedicated to Yves Saint Laurent in Paris and Marrakech this autumn.
“Yves and I loved one another: it is important to say that. And we set out to create an important new couture house and we had a magnificent success with it,” he told the Witness programme in 2016.
“But I am not a nostalgic person. This period with Yves Saint Laurent was marvellous but it is 50 years ago.”