Among the many love-hate relationships that Steve Jobs engendered during his remarkable 56 years on earth, none endured as long—nor was as fraught—as his connection with Chrisann Brennan, Jobs’ first girlfriend and the mother of his daughter Lisa.

The pair met at age 17 in 1972, as students at Homestead High School in Cupertino, Calif., and Brennan’s stormy dealings with Jobs—over his initial denials of paternity, his treatment of Lisa, and his limited financial support—continued until his death nearly four decades later. Brennan offered her unsparing take on Jobs—and becoming an “object of his cruelty”—in a 2013 memoir, entitled The Bite in the Apple.

But one till-now-unrevealed chapter of their tortured history unfolded after the period covered by Brennan’s book, during the time when her ex- was achieving his highest renown and wealth. It’s the story of how she asked Jobs, by then a billionaire, to repent for his “dishonorable behavior” with a $25 million payment to her—and another $5 million for their daughter, then 27.

Brennan, now 60, made her request in an undated, single-spaced, two-page letter, which she says she sent to Jobs in December 2005. She later provided a copy to Fortune (click here to read Brennan’s letter). A self-described “transmutational” painter and sculptor, Brennan was struggling financially then, as she had throughout her adult life. Jobs, then 50 and the CEO of both Apple AAPL and Pixar, was worth an estimated $3 billion.

“I have raised our daughter under circumstances that were all together too tough and tougher than they needed to be,” Brennan wrote Jobs. “Obviously it was all the more confusing and difficult because you had so much money….something is incomplete….I believe that decency and closure can be achieved through money. It is very simple.”

Jobs ignored her request, Brennan says. Months later, she began writing a memoir about their relationship.

More than three years after writing Jobs and asking for money, Brennan tried again. In 2009—sick, out of money, and living with friends—she contacted him again. This time Brennan offered to shelve the book (which she says Lisa didn’t want her to publish anyway) in exchange for a financial settlement.

“I am asking you for the last time to please set up a trust for me for my life,” Brennan wrote Jobs on Sept. 26, 2009, according to emails she provided to Fortune. “I do not want to cause conflict with you but I must do something. I have been ill for 3 years and I just do not have a choice anymore….No one is going to be impressed with either of us in this book and it will hurt Lisa who never deserved any of this. The choice is yours. Please consider providing me with $10,000 for a few months and working out a trust. You and I cannot talk because I am too ill and on a hair trigger…. Given my circumstance, I am moving as fast as I can to have the money I need to live, it is either you or the book.”

“I don’t react well to blackmail,” Jobs wrote back that day, copying Lisa, then 31. “I will have no part in any of this.”

(In an email, Lisa declined a request to comment for this story. A spokesperson for Laurene Powell Jobs, the Apple co-founder’s widow, said she would also have no comment.)

After falling in love in high school, Jobs and Brennan, kindred counterculture spirits, had an on-again, off-again romance over five years. They never married, but lived together for parts of that time. He got her pregnant at age 18—by their agreement, she had an abortion—then again, when she was 23.

Lisa was born in May 1978. Jobs, who had launched Apple and was already wealthy, would give his daughter’s name to one of Apple’s first personal computers. Yet he went to great lengths to deny paternity for more than two years, while Brennan cleaned houses, waited tables, and went on welfare. At one point, Jobs even swore in a signed court document that he couldn’t be Lisa’s father because he was “sterile and infertile,” and lacked “the physical capacity to procreate a child.” (He had three more children after marrying Powell in 1991.)

After a lawsuit forced Jobs to take a paternity test, leading to a court order to provide child support and reimburse the state for its welfare costs, Jobs began paying $500 a month. Apple went public a month later, giving Jobs a personal net worth of more than $225 million. While Jobs rarely visited his daughter for years, bought a mansion, and drove a Mercedes, Brennan struggled to make ends meet. In a published essay, Lisa, who became a writer, later recalled how her father “would stop by our house some days, a deity among us for a few tingling moments or hours.”

Brennan says later Jobs apologized for the way he’d treated her and Lisa. After developing a closer relationship with his daughter—who legally changed her name to Lisa Brennan-Jobs at age nine—he increased his support “in small increments,” eventually to $4,000 a month, says Brennan. “He was cheap as he could be. He under-provided for everything. It was always like pulling teeth to get him to step up.”

Over the years after their daughter’s birth, Jobs bought Brennan two cars and a $400,000 house, paid Lisa’s private school tuition, and at times offered other financial help. Despite this, Brennan filed for bankruptcy in 1996. During high school, Lisa lived with her father (and his family) for the first time. In a second essay, Lisa wrote: “Growing up I’d been very poor, very rich, and sometimes in the middle.”

Jobs’ money—and his favor—could be withdrawn at a moment’s notice. After a summertime conflict with Lisa, back home from Harvard, Jobs stopped supporting her and refused to pay her college tuition. Lisa moved in with a married couple down the street, who covered the tuition; Jobs didn’t repay them for years.

One e-book edition of Walter Isaacson’s authorized biography of Jobs quotes him saying that he didn’t attend his daughter’s 2000 Harvard graduation because Lisa “didn’t even invite me.” In fact, according to Brennan and two other sources, his daughter did invite him and he did attend. (According to a newspaper account at the time, Jobs used his daughter’s graduation to get excused from jury duty.)

After Brennan pointed out to Jobs that his official Apple biography described him as living in Silicon Valley “with his wife and three children”—“Lisa was so upset,” says Brennan—he changed it in July 2001 to “three of his four children.” In December 2004, it was changed back to “three children.”

In 2005, Brennan was again in financial distress. Although she and Jobs rarely spoke at that point, she wrote him, asking for an “acknowledgement gift” large enough to end her money troubles forever.

“By raising our daughter and raising her well, I have provided you with a means to having a relationship with her now,” wrote Brennan, explaining why she believed she deserved the payment. “I never turned her against you. I think you might have taken this for granted, but it should mean a great deal to you…

“I think you have made a lot of money for a lot of people over the years yet I wonder if anyone has done as much for you as I have with Lisa and done so without the full and sustained support that this work has realistically required.”

Brennan said she had arrived at the figure of “$25 million net” after years of consideration. She also requested $5 million for Lisa, and said she planned to give their daughter another $5 million out of her payment.

“It may make sense that when one goes through a traumatic experience over so many years that there is a need for truth and reconciliation for real closure to take place. This letter is the truth and money and appreciation represent reconciliation. I should have received the peaceful experiences that wealth provides so I could provide for Lisa as she was growing up….To me this balances what I have done for you.”

“I am requesting we close this chapter forever,” Brennan added. “Money is the only meaningful thing that can do it at this point. All the years that I have lost as a result of a sort of theft from dishonorable behavior can heal and be forgiven.”

Brennan says Jobs never responded to her letter.

Her 2009 payment request, however—offered as an alternative to publishing her memoir—brought his immediate, angry response.

“I am not trying to black mail you,” Brennan replied. “Please try to see that I would prefer to resolve things and that I have asked you, maybe poorly, to help before. I have been without a home for over a year and I [am] ill and I am fried. It would be convenient for me to die but even this does not happen. I am stuck with a body and a life, I need to do something.”

Lisa’s own relationship with Jobs remained volatile into adulthood, leading to long periods where they didn’t speak to one another. But Lisa was at her father’s bedside when Jobs died at home in Palo Alto, on October 5, 2011, at 56.

Brennan’s conflict continued with his widow. Days after Jobs’ death, from pancreatic cancer, Brennan published an essay in Rolling Stone, where she recalled their early, free-spirited romance—as well as the “all-too-often despotic jerk Steve turned into as he rose to meet the world.” This, Brennan says, got her “uninvited” from a private memorial service for Jobs on the Stanford campus.

In January 2014, she wrote Laurene Powell Jobs a certified letter, urging her to do what he wouldn’t, through a generous settlement from his estate.

“Your loyalty to Steve does not mean loyalty to his hatreds,” Brennan wrote. “….I simply never deserved the years of poverty and justifications he built up against me…

“You are in a position to help me without harm to your own life situation and children…..If you can find your way to helping so that I, as Lisa’s mother, can live in dignity and peace, we don’t need to tell anyone….this could be very quietly and legally done.”

In his estate, Jobs left their daughter a multi-million-dollar inheritance, which Lisa has used to help support her, according to Brennan. But Brennan says she never received a response to her letter from Powell Jobs. She ended her plea to Steve Jobs’ widow this way: “It is awkward between us for many reasons, but I do want you to know that I deeply appreciate what you must have gone through during all the years of Steve’s illness and then his death. I know you loved him very much. In truth, so did I.”

For more, watch what Pixar President Ed Catmull had to say about Steve Jobs:

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