Sotheby's has announced that its May 14 Contemporary Art Evening Auction will star Francis Bacon's Study for Portrait of PL, an emotionally charged depiction of his recently deceased lover.

Bacon and Lacy's relationship was notoriously violent, with Lacy once throwing Bacon through a window

The incredibly important work will auction with an estimate of $30m-40m in New York. Peter Lacy was the love of Bacon's life, who died as a result of alcoholism in 1962, just months before the painting was completed.

His death had a significant effect on the artist's career, one that is evident in almost all subsequent works. The portrait is one of many that Bacon conducted of Lacy, and is undoubtedly the most important.

Lacy was renowned for his violent personality and Bacon suffered much abuse as a result. The former fighter pilot had moved to Tangier in the mid-1950s and, although Bacon made frequent visits, the artist mainly lived in London.

Bacon only found out about his lover's death on the opening day of the 1962 Tate retrospective dedicated to his work. This cruel twist of fate would repeat itself in 1971, when he learned of the death of another other lover, George Dyer, on the day of his exhibition at the Grand Palais in Paris.

The work has not been seen in public for four decades, with the last known exhibition held in 1972 at London's Lefevre gallery. It currently belongs to a private collector, with whom it has remained since the mid-2000s.

In March, a remarkable collection of six canvas fragments from Bacon's Screaming Pope series sold at a UK auction.

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