What does one serve the Italian prime minister if he is coming to your apartment for dinner? If you’re Mr Gianni Agnelli, the renowned CEO of Fiat, the answer is simple. As his longtime cook Mr Giulio Marconi recounts in the new HBO documentary Agnelli, “Mr Agnelli called me from the office and said, ‘Let’s give him bulls’ balls.’” When the cook tried to explain that the dish would be inappropriate, his boss would have none of it. “‘My dear Giulio,’ he said. ‘What’s more beautiful than giving two testicles to a prick?’”

While Mr Agnelli, who lived from 1921 to 2003, is remembered within the fashion-media world as the Rake of the Riviera and a menswear icon, this documentary from director Mr Nick Hooker and executive producer (and erstwhile Vanity Fair editor) Mr Graydon Carter is less La Dolce Vita and more King Lear. In the filmmakers’ hands, Mr Agnelli’s story becomes a five-act tragedy that explains the tension between the devil-may-care playboy and the wily powerbroker who strove to keep post-war Italy from succumbing to Communism. The eclectic list of on-camera interviews reads like the seating plan of Annabel’s circa 1971. There are statesmen (Mr Henry Kissinger), fashion designers (Mr Valentino Garavani, Ms Diane Von Furstenberg), a CIA agent (Mr Frick Vreeland) and Italian aristocrats in spades, including Mr Agnelli’s sisters, brother-in-law, nieces, nephews and grandchildren.

For the film’s director, Mr Agnelli’s life embodied the oft-quoted line from the novel The Leopard, “If we want things to stay as they are, things will have to change”. But within the gyre of mistresses, fast cars and nuits blanches (as the documentary claims he dubbed his cocaine benders), there were two constants. “Number one is that the Agnelli family controls Fiat and, like an alloy, they are fused to Fiat, and Fiat is fused to Turin, and Turin is fused to Piedmont, and Piedmont is fused to Western Europe, the US and the atlantic Alliance,” says Mr Hooker. “And that alliance guarantees freedom. And the other non-negotiable for Gianni is this exquisitely engineered life with an extreme, next-level aesthetic.”

After looking at countless images of Mr Agnelli and even seeing his closet full of his bespoke suits from Milan tailor A. Caraceni, Mr Hooker suggests that his sartorial signatures may have been his way of rebelling against the statesman-like role he had to play. “His mother misbehaved, but looked elegant doing it,” he says of Ms Virginia Bourbon del Monte dei principi di San Faustino, an eccentric who went around with a pet leopard but lost custody of her seven children after Mr Agnelli’s father died in a seaplane crash in 1935. “So these touches were like little flashes of personality through his armour.”

Whatever their psychological underpinnings, MR PORTER is always happy to learn a thing or two from this OG Influencer.

“Everyone tried to copy him by putting the watch on top of the shirt,” says Valentino in the documentary. “I copied him myself.” Here, Mr Agnelli displays two of his style signatures: wearing his watch over his cuff and his penchant for a blue Oxford shirt, a colour that nearly every man looks good in, particularly those with an olive complexion who tan easily. Mr Agnelli first visited the US in 1938, but it is unclear when he discovered this American collegiate staple.

In August 1962, Ms Jacqueline Kennedy and her four-year-old daughter Ms Caroline Kennedy came to Ravello for an Italian holiday, and Mr Agnelli did his bit for Italian-American relations by taking the First Lady on a trip to Capri aboard his yacht Agneta. Here, he wears a style of summer shirt known as a popover, which has been having something of a revival of late. When images of Mr Agnelli and Ms Kennedy made their way back to Mr John F Kennedy, the documentary claims the president famously sent his wife a telegram that read “More Caroline, less Agnelli”.

There’s nothing like a pair of hiking boots to make a suit feel less fussy, but this is a case where Mr Agnelli comes by a style affectation honestly, if dishonourably. The legend goes that in 1952, his girlfriend, Ms Pamela Digby, arrived late to a party and caught him with another woman, Ms Anne Marie d’Estainville. As he drove Ms d’Estainville back to her house in Cap Martin, he crashed his Ferrari into the back of a lorry. Ms d’Estainville emerged from the wreck intact. Mr Agnelli’s leg was shattered. For the remainder of his life, he refused to walk with a cane and instead found stylish work-arounds, be it skiing with a leg brace or forgoing wingtips for boots with greater support.

Divorced from Sir Winston Churchill’s son Randolph, and hoping to become Mrs Gianni Agnelli, the colourful and controversial Ms Digby kept watch over her beau as he recovered from the car accident. (Ms Digby was later rather unkindly described by one wit as “a world expert on rich men’s bedroom ceilings”.) Mr Agnelli’s sisters had had enough of her and brought their friend Ms Marella Caracciolo di Castagneto to the hospital to cheer their brother up. He fell for this Neapolitan aristocrat. They married in 1953, and she in turn became known as The Swan. Her elegant neck, which captivated designers including Valentino, the writer Mr Truman Capote and photographer Mr Richard Avedon, gets an appreciative look from her tuxedoed and pomaded husband in Monte Carlo circa 1959.

Arguably better known for pioneering the sprezzatura affectation of leaving the thinner back blade of his neckties longer than the front, Mr Agnelli shows a variation on the theme here, wearing it outside his V-neck sweater. No one seems to look askance as he addresses the good gentleman of the Milan Stock Exchange.

Mr Agnelli loved to leap from his helicopter into the Mediterranean as a kick-off to a weekend at his villa on the Riviera. Or when visiting friends’ houses, he liked to drop out of the sky into their swimming pools. As his cook relates in the documentary, Mr Agnelli was happiest when in constant motion and once suggested they take the helicopter to the Matterhorn for a couple of hours’ skiing. Here, he touches down at Sestiere, the ski resort north of Turin that his grandfather built.

Mr Agnelli loved flannel, and flannel loved him back. The heavy fabric has the unique ability to make its wearer look both powerful and a bit louche, so it is perfect for those days when a crucial meeting is immediately followed by a big night out. When this photo was taken in late 1969, Italy was heading into a period of perpetual night known as the Years of Lead, thanks to left-wing terrorist groups, including the Red Brigades, kidnapping and murdering a Fiat executive and a former prime minister. Other tragedies followed for Mr Agnelli, most horrifically the suicide of his only son, Mr Edoardo Agnelli, in 2000. One can’t help but look at this photo and think that, for the Rake of the Riviera, his days of la dolce vita were beginning to slip away.

In addition to the presidential motor yacht Honey Fitz, President Kennedy, a sailor at heart, also spent time on Manitou, an 18.9m racing craft that was retrofitted to be a floating White House. On the face of it, this image from September 1962 is a study in casual dressing contrasts, with Mr Kennedy favouring a preppie uniform of windbreaker, crew neck and chinos to Mr Agnelli’s more continental rollneck, blue slacks and loafers. For the Fiat chairman, who had fought for the Axis powers during WWII, these cosy moments with the First Couple of the United States were subtle statesmanship at its best.

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