Marianne Ihlen's influence on Leonard Cohen lingered long after their time together, and now the public is poised to get a deeper glimpse into their relationship.

More than 50 letters the Canadian poet-turned-singer-songwriter penned to her — correspondence offering an intimate, personal glimpse into his thoughts during a key time in his artistic career — will be displayed in New York and offered at auction this spring, 2½ years after his death at age 82.

The Christie's sale is titled: "Write Me and Tell Me Your Heart: Leonard Cohen's Letters to Marianne." The online auction, slated to run June 5 through June 13, features largely handwritten as well as some typewritten letters Cohen penned to the woman who inspired songs like So Long, Marianne and Bird on a Wire.

Postcards, some photos and a few personal items are also included among the lots, which carry presale estimates from $300 up to $12,000 US.

The online auction, slated to run June 5 through June 13, features largely handwritten as well as some typewritten letters. Postcards, some photos and a few personal items are also included among the lots, which carry presale estimates from $300 up to $12,000 US. (Christies.com)

The letters "aren't just everyday little letters," but offer authentic insight into the famed singer-songwriter, according to Ira Nadel, author of the biography Various Positions: A Life of Leonard Cohen.

"These are substantial letters that describe his feelings in becoming an artist and, in particular, becoming a singer," said the B.C.-based professor, biographer and literary scholar, who was permitted an early review of the collection by Christie's.

Your letters, they all say that you're beside me now,

Then why do I feel alone?

I'm standing on a ledge and your fine spider web,

Is fastening my ankle to a stone.

So Long, Marianne.

— by Leonard Cohen

'It's Leonard Cohen offstage'

The correspondence begins in 1960, just months after the Canadian poet first met Ihlen on the Greek island of Hydra, where the former Norwegian model and young mother had become estranged from her novelist husband. For a time, she and her son Axel made a home with Cohen on the island, a haven for artists and intellectuals.

Over the next 20-odd years, he would write to her from wherever he was — Montreal to Tel Aviv, New York to Havana — sharing insight into his life as he was expanding his artistic career. With a book of poetry already under his belt when he met Ihlen, the Canadian bard details his ventures into writing novels and his struggle to become a singer-songwriter.

In multiple letters, Cohen expresses a yearning for Ihlen and a life with her, which is then juxtaposed against a yearning for independence.

Cohen is seen performing on CBC Television in 1967. In his letters to Ihlen, Cohen shares insight into his life as he was expanding his artistic career, detailing his ventures into writing novels and his struggle to become a singer-songwriter. (Michael Reichmann/CBC)

"You read these letters and you get a real sense of, 'Who is this person? What is he like? What excites him? What depresses him? What distracts him?' This is the kind of detail you will find in these letters," Nadel said.

"It's Leonard Cohen offstage. He's not performing here. He is not responding to an audience."

The letters, which continue long after the pair had separated as a couple, also show how Ihlen "remained critical in terms of his romantic ideas," Nadel noted.

Their relationship resurfaced again in summer 2016. It emerged that as Ihlen lay on her deathbed in Oslo, Cohen sent a message to her suggesting he would soon follow her. Cohen died four months later.

In an ideal world, Nadel said, he would love if the letters were purchased and donated to an institution, for instance, the Leonard Cohen archive at the University of Toronto's Thomas Fisher Rare Book Library. Cohen donated dozens of boxes of correspondence to the library in 2003.

However, Nadel predicts the auction will garner the attention of Cohen devotees everywhere.

"It's going to be very hard to trace [the letters], I think, once the auction is finished because they will be dispersed around the world… Leonard's fans are, of course, worldwide."