Passionate letters sent by Mick Jagger to his secret lover in the summer of 1969 have sold for £187,250.
The Rolling Stones front man penned the love notes - which include song lyrics and a band playlist - to singer Marsha Hunt.
The American, who was the inspiration for the 1971 Stones hit Brown Sugar, had expected to receive between £70,000 and £100,000 for the 10 letters.
After the sale, Hunt said: "The passage of time has given these letters a place in our cultural history.
"1969 saw the ebbing of a crucial, revolutionary era, highly influenced by such artists as The Beatles, The Rolling Stones, James Brown and Bob Dylan.
"Their inner thoughts should not be the property of only their families, but the public at large, to reveal who these influential artists were - not as commercial images, but their private selves."
The auction house's books specialist Gabriel Heaton said: "These beautifully written and lyrical letters from the heart of the cultural and social revolution of 1969 frame a vivid moment in cultural history.
"Here we see Mick Jagger not as the global superstar he has become, but as a poetic and self-aware 25-year-old with wide-ranging intellectual and artistic interests."
The letters were penned by Jagger while filming Ned Kelly in Australia, at a time when his relationship with Ms Hunt was a closely-guarded secret.
In a separate auction, Bonhams sold dozens of items from a Beatles collection once owned by the legendary band's lead guitarist George Harrison.
His leather jacket - worn on stage during the early 1960s in Hamburg and The Cavern Club - sold for £110,450.
Also up for grabs were a pair of Harrison's custom-made leather boots from around 1964, and an orange shirt worn during his famous charity event, the Concert For Bangladesh in 1971.
The boots sold for £61,250, far above the top presale estimate of £15,000.
Bonham's director of entertainment memorabilia, Stephanie Connell, said: "This leather jacket is instantly recognisable and was an important part of the Beatles' image in their early years.
"It is extremely exciting to see such an iconic part of Beatles history emerge onto the market, this fresh piece of important music memorabilia never offered at auction before is sure to garner significant interest during the sale."
A guitar used by Sir Paul McCartney in the 1950s - before the Beatles formed - sold for £43,250.
The total for the Bonhams sale, which also included items worn by Eric Clapton in the 1960s, was £624,619.