A collection of ten letters from a young Lucian Freud to poet and critic Stephen Spender will go on sale at Sotheby’s London as part of the Contemporary Art Day Auction on July 2, and are expected to fetch up to £42,000 ($64,000) combined.

The letters have come to auction after 70 years with other items from the Spender family, including two paintings by Frank Auerbach, whose canvas The Head of Gerda Boehm (1961) could fetch up to £350,000 ($535,000) (see Lucian Freud’s Auerbach Collection Accepted in Lieu of Taxes by UK Government).

Freud’s letters are part of the intimate correspondence between the two men, which conveys great fondness between them and has lead some people to believe that they may have been more than friends.

The letters were exchanged between 1939 and 1942—while Freud studied under Cedric Morris at the East Anglian School of Painting and Drawing in Essex—and some of them feature illustrations by both Freud and Spender.

Lucian Freud Letter to Stephen Spender (1940)
Photo: Courtesy Sotheby’s London

“While relatively little is known about Freud’s teenage life, the emergence of these letters is a sensational moment, providing a glimpse into the workings of a truly artistic mind,” Oliver Barker, senior international specialist in contemporary art at Sotheby’s, said in a statement.

“More than just letters, they are artworks in their own right,” Barker added. “Filled with drawings and watercolors, they show the workings of the artist, reflecting his artistic output at the time.”

In one letter, Freud, who was in his teens and the younger of the two men by thirteen years, drew a self-portrait. Another letter contains a depiction of two figures hugging with the words “thinking of you.”

Lucian Freud had a reputation for being very private about his teenage years, and the emergence of these letters is being seen by some as an explanation for his secretive behavior.

Lucian Freud Letter to Stephen Spender (circa 1939-1940)
Photo: Courtesy Sotheby’s London

“From the letters it looks like Dad was in love with Lucian; whether Lucian was in love with Dad is another matter,” Matthew Spender, the son of Stephen Spender, told the Daily Mail. “Lucian, especially as a young man, was the kind of young man that my father would be incredibly attracted to. If you think of the other young men in his life, they’re physically very similar to Lucian.”

“But Lucian also was the most tremendous flirt. He inherited from his grandfather (Sigmund Freud) this ability to get under people’s skin and manipulate them,” Spender added.

In his later life, Freud is thought to have had as many as 50 female lovers in addition to relationships with men, was married twice, and fathered 14 children (see Lucian Freud’s Willed Millions Stay Secret and Lucian Freud’s Illegitimate Children Sue Over the Late Artist’s Will).