Damien Hirst’s former manager Frank Dunphy, the mastermind behind some of the artist’s savviest business moves, is putting more than 200 works from his collection on the auction block at Sotheby’s London in September. The Irish-born former accountant and financial advisor also worked with Hirst’s fellow YBAs Tracey Emin and Jake and Dinos Chapman, as well as the British actor Ray Winstone.

Damien Hirst, Smashing Yellow Ball at Peace Painting (2008). Courtesy of Sotheby’s.

During his 15-year working relationship as Hirst’s financial advisor, Dunphy is credited with facilitating deals such as the private sale of Hirst’s Hymn in 1999, the first work by the artist to sell for more than £1 million, the repurchase of nearly a third of Charles Saatchi’s collection of early works in 2003, and two unprecedented direct studio-to-auction house sales of Hirst’s work at Sotheby’s in 2004 and 2008.

Andy Warhol, Dollar Sign (1982). Courtesy of Sotheby’s.

Hirst first met Dunphy over a game of snooker at the Groucho Club, a popular London artist hangout, Sotheby’s specialist Olly Barker told artnet News. “Damien’s mother was a member as well, and it was her who who first approached Frank to help her son out because Damien had a huge amount of financial success but was young and didn’t really know how to handle the business side of his affairs,” Barker says. The became friends and worked together until Dunphy retired in 2010.

Damien Hirst, Psst (1997). Courtesy of Sotheby’s.

Unsurprisingly, Hirst’s work makes up a large part of the collection that Dunphy and his wife Lorna have amassed over the past three decades. Some of the works were gifts: Hirst gave Dunphy one of his pill cabinet works Psst (1997) when his advisor was ill (est. £60,000–80,000); Bust of Frank (2008) was for Dunphy’s 70th birthday (est. £25,000–35,000), and Hirst gave Dunphy the butterfly painting Smashing Yellow Ball at Peace Painting (2008) as a retirement gift (est. £100,000–150,000).

But the Dunphys also bought high-caliber works by other renowned YBAs, including Tracey Emin, Michael Craig-Martin, and Rachel Whiteread. They’re also selling blue-chip works such as Lucio Fontana’s Concetto Spaziale, Attese (1961) (est. £600,000–800,000), which is the most expensive lot in the sale; an Andy Warhol Dollar Sign painting (1982) (est. £200,000–300,000); and Richard Prince’s Untitled (Gene Pitney) (2011), which Dunphy bought from Gagosian Gallery.

Lucio Fontana, Concetto Spaziale, Attese (1961). Courtesy of Sotheby’s.

“The art scene has been our life for the past 30 years,” the Dunphys said in a joint statement. “Living with the art has been like living with our friends. Much of it is steeped in happy memories, and so much of it we bought ourselves simply because we loved it. But time waits for no man, and the time has come to say goodbye to some of the art, though not the memories nor the friendships.”