Leonard Cohen’s love letters to his muse Marianne Ihlen have fetched $876,000 (£692,190) at auction, with many going for more than five times their pre-sale estimates, Christie’s auction house said.

The collection of more than 50 love letters written by the singer-songwriter chronicles their 1960s love affair and his transition from a struggling poet to a famous musician.

The most expensive letter, in which Cohen wrote in December 1960 about being "alone with the vast dictionaries of language," was expected to fetch up to $10,000 (£7,900) but in fact sold for $56,250 (£44,445).

A 1964 letter, in which the Canadian-born poet wrote "I am famous but empty," went for $35,000, Christie’s said.

Cohen and the Norwegian-born Ihlen met on the Greek island of Hydra in 1960 and she became the inspiration for several of his best-known songs, including "Bird on a Wire," "Hey, That’s No Way to Say Goodbye," and the 1967 track "So Long, Marianne."

'Write me and tell me your heart', Montreal, 15 February 1961 credit: Christie's

The top lot in the five-day online auction was an Italian bronze bell dating from the 15th or 16th century that hung in the Hydra home that Cohen and Ihlen once shared. It fetched $81,250 - far exceeding its pre-sale estimate of $12,000.

The bell is believed to have inspired the lines, "There is a crack, a crack in everything" in Cohen’s 1992 release "Anthem."

One early letter in the collection marks Cohen’s first separation from his muse after meeting her earlier in the year. Written from the beaches of Tel Aviv, Cohen ends the letter: "It’s hard to write you. The surf is too loud. The beach is too crowded, and you’re too much in my heart to put anything down."

Estimated to sell for between $6,000 and $9,000, it sold for $20,000.

Leonard Cohen in 1980 credit: Evening Standard/Getty

The pair, who remained friends after their romance ended, died within months of each other in 2016.

Ihlen died of leukemia in Oslo in July aged 81 and Cohen, who was also suffering from leukemia, died in November at the age of 82.

The bulk of the letters span from 1960 to 1979 and were sold by Ihlen’s family. Christie’s did not reveal the identify of the buyers.