Yves Saint Laurent and his partner Pierre Bergé shared a passion for refined and beautiful objects throughout their on-off romance and business relationship that lasted half a century.

Their homes were filled with an eclectic mix of priceless paintings, sculptures, objets d’art, archaeological artefacts, African masks, books and manuscripts, all chosen carefully to sit well together.

Marrakesh hosts Yves Saint Laurent museum and iconic looks

After Saint Laurent died in 2008 of brain cancer, Bergé, co-founder of the YSL haute couture house, began disposing of key parts of the unique collection to fund two cultural foundations dedicated to the designer.

Now, after Bergé’s death aged 86 last September, preparations are under way for what is expected to be the final big auction of personal and private items belonging to one of France’s most passionate collectors.

A total of about 1,200 objects, the contents of Bergé’s four luxury properties including his residence in Rue Bonaparte on Paris’s Left Bank – an 18th century house where Édouard Manet was born in 1832 – and the Villa Mabrouka in Tangiers, Morocco, that he shared with Saint Laurent, will be sold by Sotheby’s in October.

The sale of works, from antiquity to modern and much in between including tableware and furniture, will take place over three days. It will be followed a few months later by an auction of books and manuscripts from Bergé’s celebrated library, including first editions of Gustave Flaubert, Charles Dickens, Samuel Johnson and Oscar Wilde.

Among the highlights of the auction, in association with Pierre Bergé & Associés, will be 10 paintings from the 1950s by the French expressionist Bernard Buffet, who was Bergé’s lover until he met Saint Laurent in 1958, and a Picasso sculpture called Masque, produced in 1961.

Luxury News Round-Up: Anthony Vaccarello debuts for Yves Saint Laurent and Peter Cheung talks about his obsession with cashmere

The sale is being overseen by the businessman’s long-time partner and legal heir, the American landscape architect Madison Cox, 59, whom married Bergé in May 2017, months before his death.

“Part of [Bergé’s] philosophy was you can’t take it with you, the only thing you can do is to transform these objects into future projects,” Cox told the Guardian.

“My number one concern is the longevity of the foundation in France and Morocco. He made the donations he wanted to friends and family, now a new chapter has opened. For me, it’s important to continue the process he began.”

Bergé began that process in 2009, shortly after Saint Laurent’s, death with a three-day auction of 700 artworks, including paintings by Henri Matisse, Marcel Duchamp, Constantin Brâncuși, James Ensor, Piet Mondrian and Giorgio de Chirico. Described as the sale of the century, it raised 374 million (US$441 million) – a record for a single-owner collection.

In a series of sales in 2015, Bergé sold his much admired collection of books, including a first edition of The Confessions of St Augustine, a copy of Dante Alighieri’s Divine Comedy from 1487; William Shakespeare’s Comedies, Histories, & Tragedies printed in London in 1664, and handwritten notes for the Marquis de Sade’s last erotic novel.

Mario Tavella, the chair of Sotheby’s Europe, said the wide range of objects being catalogued for the auction showed Bergé’s eclectic and “super cultivated” tastes and his “inquisitive mind”.

Yves Saint Laurent's legacy will be preserved in museum exhibitions in Paris and Marrakech in 2017

“He collected from every century and every area. I cannot think of a single domain that is not represented in this sale,” Tavella said.

“Right now I cannot tell you exactly how many lots there will be at auction because each time we open a drawer in one of these properties, we find something else.”

Money raised from future auctions will go to the Pierre Bergé-Yves Saint Laurent Foundation, which has opened two museums: one in the former YSL haute couture house at 5 Avenue Marceau, the other near the Jardin Majorelle in Marrakech, which Bergé and Saint Laurent bought to save from a hotel development.

In letters he wrote to Saint Laurent after the designer died, Bergé pays tribute to the support Cox had given him. “Thanks to Madison, probably, I weathered the storm … he gave me what I needed: his youth, culture, courage, integrity, love.”

New make-up: YSL Beauty Club launches Tatouage Couture collection

Cox said he was trying to avoid sentimentality when dealing with the auction. “These are pieces I’ve lived with most of my adult life having known Pierre Bergé and Yves Saint Laurent since my early 20s, but I have adopted the policy of not holding pieces back,” he said.

“I think it’s important to honour the legacy, as Pierre Bergé did when Yves Saint Laurent passed away. One starts looking and thinking: ‘Oh, it would be wonderful to keep those 18th-century Chinese plates and have breakfast off them’ … but it’s easier to draw line.”

Want more stories like this? Sign up here. Follow STYLE on Facebook, Instagram and Twitter