Hal Ashby’s 1970 directorial debut, The Landlord, begins with a baffling scene, just a few seconds long, featuring none of the characters from the film. We open on a wedding party at the altar as the bride leans over to kiss the best man. Viewers had no way of knowing that this footage came from Hal Ashby’s actual wedding to his (fifth) bride, that the recipient of the smooch was the film’s producer, Norman Jewison, or that the kiss itself was symbolic thanks for launching Ashby’s directorial career.

In the late 1960s, Ashby and Jewison were one of the great creative teams in Hollywood. The relationship began with Ashby serving as editor extraordinaire on The Cincinnati Kid and The Russians Are Coming, the Russians Are Coming. By In the Heat of the Night, Ashby had ascended to associate producer. By The Thomas Crown Affair, their relationship was almost symbiotic. They were “brothers,” Ashby said. When scheduling issues prevented Jewison from directing The Landlord, adapted from the book by Black American novelist Kristin Hunter, he offered the gig to Ashby.

“In all the time I had known Norman,” Ashby remembered, “we had never once touched upon the subject [of Ashby’s directing] and here this beautiful, sensitive dude was standing there asking me about my dreams.”

Ashby and Jewison were something of an odd couple. “Hal [was] about as far away from Norman in personality” as one could be, said David Picker, former C.E.O. of United Artists. Ashby was the freewheeling, younger creative who dabbled in LSD and worked obsessively in the editing room for days on end, while Jewison was the family man, trusted by suits to manage budgets and schedules. “I cannot think of anybody who, working on the same films, brought such different personal attitudes towards them,” Picker said. Whatever their differences in lifestyle and temperament, their partnership amounted to magic on the screen.

By the early 1970s, however, the relationship was fraying. Following the assassination of his friend Bobby Kennedy and the implosion of his attempted adaptation of William Styron’s The Confessions of Nat Turner, in 1968, Jewison fled Hollywood to film Fiddler on the Roof in the U.K. and Yugoslavia. He wouldn’t return for a decade. Ashby, meanwhile, struggled to get his own directorial projects off the ground. A bruising contract renegotiation with United Artists left him feeling vengeful and paranoid.

“I cannot think of anybody who, working on the same films, brought such different personal attitudes towards them.”

“There isn’t a day when I don’t think how much positive energy they drain away from us with their negativism,” Ashby wrote to Jewison. “Beyond a doubt they are all the prize assholes of all time, who have not one ounce of talent aside from that of really knowing how to be super liars, cheats, and generally bad people. As stated, fuck them.”

Then, in a March 1971 letter to Irving Klein, Jewison’s U.S. manager, Hal effectively ended the partnership with his friend and mentor. Ashby lambasted Klein for allegedly withholding wages for Harold and Maude (in case Ashby quit the project), and using the withheld funds to pay William Morris agents without his consent. Ashby characterized the move as “nothing short of disgraceful, disrespectful, shocking, and dishonest,” motivated either by “stupidity and ignorance” or “some weird kind of malice.” Ashby concluded by asking “to be released from ever having one God damned thing to do with the business side” of Jewison’s production company, “while you my dear Mr. Klein, can fuck off!”

For decades, industry players would wonder what happened between Ashby and Jewison. “Of all the stories I don’t know,” said their mutual friend Patrick Palmer, “that’s the one that mystifies me the most.” If the Atlantic Ocean had come between their friendship, Ashby’s scalding hatred of Jewison’s business representatives hastened the demise of their professional relationship.

You can find traces of Jewison in Ashby’s great films of the 1970s, such as the hilarious homage to Thomas Crown’s iconic kiss in Being There (1979). Ashby continued to work with Jewison’s collaborators, including Haskell Wexler, on Bound for Glory (1976) and Coming Home (1978). But it was never the same between Hal and Norman. Both men realized what they’d had, and what they’d lost.

“Being loved by you has been a very groovy trip for me,” Ashby once wrote to Jewison. “I can’t even imagine what my life would have been without it.”

Asked about their relationship in the 2018 documentary Hal, Jewison, who had not had regular contact with Ashby for 45 years—half of his life—began to cry. “I don’t think I ever loved another man as much as I did Hal,” he said.

Ira Wells’s Norman Jewison: A Director’s Life is out now from Sutherland House