On the morning of the sixth of May 1960, Anthony Armstrong-Jones stood at the altar of Westminster Abbey waiting for the most photographed woman in the world to walk toward him. Princess Margaret, the younger sister of Queen Elizabeth II, moved up the long aisle in a gown of silk organza chosen with deliberate simplicity so her small frame would not be swallowed by the vast abbey, a diamond tiara on her head. Roughly three hundred million people around the world watched on television, the first great royal wedding of the age of broadcasting. The bride was twenty-nine, the groom thirty, and the country believed it was witnessing a fairy tale, a love match that had broken every old rule.

Nobody in the abbey knew that the man at the altar was standing on top of a secret that could have brought the whole occasion crashing down. And nobody would know it for more than forty years. Only weeks before the wedding, the groom’s chosen best man had quietly withdrawn. He was a close friend named Jeremy Fry, and he carried a minor conviction from several years earlier connected to his private life, at a time when relationships between men were still illegal in Britain.

It was decided that he could not stand at the altar at a royal wedding. A doctor friend named Roger Gilliatt stepped in at the last minute. But there was something else. Fry’s wife, Camilla, was pregnant.

Within weeks of the royal wedding she gave birth to a daughter named Polly. Decades later, in 2004, a DNA test confirmed what a few insiders had long whispered: the child’s father was Anthony Armstrong-Jones. He had been involved with his best man’s wife during the very months when he was courting the queen’s sister. The bride almost certainly did not know.

She had her own reasons for choosing this man, and they had very little to do with him. To understand those reasons, you have to go back to a little girl who grew up knowing she would always come second. Margaret Rose was born on the twenty-first of August 1930 at Glamis Castle in Scotland, the ancestral home of her mother’s family. Her father was Prince Albert, Duke of York, a shy, decent man with a stammer who never expected to be king.

Her mother was Elizabeth, Duchess of York, warm and charming and much tougher than she looked. Her sister, Elizabeth, known in the family as Lilibet, was four years older. For the first six years of her life, it was a quiet, almost ordinary upbringing by royal standards, in a townhouse at 145 Piccadilly with a Scottish governess the girls called Crawfie. Then in December 1936 everything changed.

Their uncle, King Edward VIII, gave up the throne to marry the American divorcée Wallis Simpson. Their father became King George VI overnight, and their sister became heir to the throne. Margaret was six. Elizabeth was now being prepared for the crown.

Margaret was not being prepared for anything in particular. She was the spare, and she made up for it by being the most delightful, mischievous child in the house. She sang, she did impressions of visiting dignitaries, she played the piano by ear, and she had a quick, sharp wit that made everyone laugh. Her father adored her.

He famously described his elder daughter as his pride and his younger daughter as his joy. She was allowed to get away with things her sister never would have dreamed of. During the Second World War the girls spent much of their time at Windsor Castle, where they put on Christmas pantomimes, and Margaret was always the star. By the time she was a teenager she had grown into a strikingly beautiful young woman, petite, with enormous blue eyes and a flawless complexion.

She loved everything her sister was cautious about: parties, dancing, jazz, nightclubs, late nights, and cigarettes in long holders. After the war, when Britain was gray, rationed, and exhausted, she became a symbol of glamour and fun. Photographers followed her everywhere. The newspapers linked her to one eligible young aristocrat after another, but none of those well-born young men was the one she fell for.

The man she actually loved was already inside the palace walls. He was married, sixteen years older than her, and he worked for her father. His name was Peter Townsend, and he had been one of the heroes of the Battle of Britain in 1940, a fighter pilot in the Royal Air Force who had shot down enemy aircraft over the English coast and had been wounded in combat. He was tall, handsome, gentle, and softly spoken, exactly the kind of man wartime Britain admired most.

In 1944 he was appointed an equerry to King George VI, becoming one of the king’s personal attendants, traveling with him, organizing his days, living in close contact with the royal family. The king, himself a shy man, liked him enormously. Townsend’s calm manner and quiet courage appealed to him, and over the years he came to treat him almost like a son. Townsend was married.

His wife was named Rosemary, and they had two young sons. When he joined the royal household, Princess Margaret was just fourteen. Over the following years she grew up with him around. He accompanied the family on their long tour of South Africa in 1947, and on those rides across the veldt the seventeen-year-old princess and the war hero spent a great deal of time together.

By the end of the 1940s his own marriage was falling apart, and her feelings for him were deepening into something serious. Then, on the sixth of February 1952, King George VI died in his sleep at Sandringham. He was only fifty-six. Margaret was twenty-one and devastated.

She had lost the person who had always made her feel special. Her sister became queen at the age of twenty-five and was suddenly consumed by the duties of the crown. Her mother, grieving, withdrew to Scotland for a time. The one person who seemed to understand what she was going through was Townsend, who had moved to her mother’s household.

Later that year his divorce went through. By early 1953 he and Margaret told her sister that they were in love and wanted to marry. The new queen was sympathetic. She was fond of both of them.

But the situation was enormously complicated. The Church of England, of which the monarch is the head, did not allow a divorced person to remarry in church while their former spouse was still alive, and Townsend’s former wife was very much alive. Only seventeen years earlier the family had been shaken to its foundations when a king gave up the throne to marry a divorced woman. The abdication was still a raw wound.

The idea of the king’s daughter marrying a divorced man was to many people in the palace and in government unthinkable. There was also a law standing in the way: under the Royal Marriages Act of 1772, members of the royal family under the age of twenty-five needed the monarch’s permission to marry. Margaret was twenty-two. The queen asked the couple to wait.

Then, on coronation day, the second of June 1953, the secret slipped out in the smallest possible way. Outside Westminster Abbey, as the royal party waited, photographers noticed the princess reach up and brush a piece of fluff from the front of Townsend’s uniform. It was a tiny, intimate gesture, the kind of thing a woman does for the man she loves, and it went around the world. Within days the foreign press had the story.

The British newspapers soon followed. The palace’s answer was to separate them and hope the feeling faded. That summer the princess traveled with her mother on a tour of Southern Rhodesia, in what is now Zimbabwe. Before she left, she and Townsend said goodbye at Clarence House, and she was reassured that he would still be in Britain when she came home.

He was not. While she was away he was posted abroad as an air attaché at the British embassy in Brussels, and he left the country before she returned. She came home to find him gone. For the next two years they were kept apart, with only letters and telephone calls between them.

There was one date they were both waiting for. On the twenty-first of August 1955, Margaret would turn twenty-five, and under the Royal Marriages Act she would no longer need her sister’s permission. She could give formal notice, and unless Parliament objected within a year, she could go ahead. As that summer came round, the whole country was waiting too.

Newspapers ran countdowns. Crowds gathered outside Balmoral on her birthday. The question was on every front page: would she marry him? In October 1955 Townsend came back to London, and the frenzy became almost unbearable.

Photographers camped outside every house they visited, and every glimpse of the two of them together was reported in detail. Opinion polls suggested that much of the public wanted her to marry the man she loved. But the government, the church, and a large part of the establishment did not. The prime minister at the time was Sir Anthony Eden, himself divorced and remarried, a detail that did not go unnoticed.

His cabinet discussed the situation, and it was made clear to the princess that the path would not be simple. By the accounts that have come out since, she understood that marrying Townsend would mean giving up her place in the line of succession and marrying in a civil ceremony rather than in church, and she feared it could mean losing her official role and the income that came with it. Papers released many decades later suggested the government may have been prepared to be more flexible about her title and allowance than she believed at the time. But what mattered in October 1955 was what she was told and what she believed.

On the thirty-first of October 1955 she issued a short public statement. She had decided not to marry Peter Townsend, she said. She was mindful of the church’s teaching that marriage was for life, conscious of her duty to the Commonwealth, and she had reached the decision entirely alone. She thanked the public for their concern and their good wishes.

The statement was written in her own words, carefully worded so that nobody else could be blamed. But everybody understood what it meant. The princess had been asked to choose between the man she loved and the life she had been born into, and she had chosen duty. Townsend left on a long journey around the world.

She went back to official engagements and late-night parties, and for the next few years she seemed to many people restless and unhappy. What nobody knew was that in the middle of that restlessness she was quietly meeting someone entirely different, and the moment that pushed her into his arms would arrive in the form of a single letter. Anthony Charles Robert Armstrong-Jones was born on the seventh of March 1930 in London, which made him just five months older than the princess. His background was comfortable and artistic but not happy.

His father, Ronald Armstrong-Jones, was a barrister. His mother, Anne Messel, came from a wealthy and creative family; her brother was the celebrated stage designer Oliver Messel. His parents divorced when he was a small boy, and his mother remarried, becoming the Countess of Rosse and having two more sons. By many accounts she lavished affection on her new family and was distant towards the children of her first marriage.

At the age of sixteen, while a pupil at Eton, he caught polio. He spent months in a hospital in Liverpool, and by the account he gave later in life his mother hardly came to see him at all. His sister Susan was one of the few people who visited regularly. The illness left him with one leg shorter than the other and a slight limp he carried for the rest of his life.

That experience left a mark on him. People who knew him well described a man who could be enormously charming and funny and who also had a cold, guarded streak, a way of keeping people at a distance and sometimes turning on those closest to him. He went to Jesus College, Cambridge, to study architecture but did not do much studying. He did row the Cambridge crew to victory over Oxford in the Boat Race of 1950.

Shortly afterwards he failed his exams and left the university without a degree. His family was unimpressed when he announced he wanted to become a photographer, which at the time was not considered a particularly respectable career for a young man of his background. He went to work as an assistant to Baron, one of the best-known society photographers in London, then set up on his own in a small studio in Pimlico. He was very good.

Instead of stiff formal portraits, his subjects jumped, laughed, and moved, and his pictures of theater stars and dancers filled the magazines. By the late 1950s he had even been asked to take official photographs of members of the royal family, including portraits of the queen’s children. He lived in a bohemian world of artists, writers, designers, and dancers, a world where people slept late, drank, argued about ideas, and had love affairs with both men and women. It was about as far from palace life as it was possible to get.

In February 1958, at a small dinner party given by a friend, Lady Elizabeth Cavendish, he was seated near Princess Margaret. She was fascinated. He did not bow and scrape. He teased her, talked about things she knew nothing about, and treated her not as a princess but as a woman.

Soon they were meeting in secret. He had the use of a small, shabby room in an old building on the River Thames at Rotherhithe, in the working docklands of East London. There, far from the palaces, the two of them could cook simple suppers, drink wine, watch the barges go by on the river, and behave like any young couple. For a woman who had spent her entire life under watch, it was intoxicating.

Remarkably, the press never found out. Then, in the autumn of 1959, a letter arrived for her. It was from Peter Townsend, writing to tell her personally, before she read it anywhere else, that he was going to marry again. His bride was a young Belgian woman named Marie-Luce Jamagne, still in her early twenties.

According to those close to her, she received that letter and that same evening decided to accept Armstrong-Jones. A secret engagement followed. Townsend married his young bride on the twenty-first of December 1959. The engagement between the princess and the photographer was kept secret for weeks, partly because of timing: the queen was expecting her third child, and it would not have been proper to announce the news before the baby arrived.

Prince Andrew was born on the nineteenth of February 1960, and a week later, on the twenty-sixth of February, the engagement was announced from Clarence House. The country was astonished. Almost nobody had heard of Anthony Armstrong-Jones, and the handful who had knew him as a fashionable young photographer. Some members of the aristocracy were openly disdainful.

His bohemian friends were equally surprised, and several wondered privately how someone so independent would cope with life inside the royal family. There were also questions about the princess’s motives. It was only weeks since Townsend’s wedding. People who knew her well suspected that at least part of what drew her to this marriage was the wish to show the world, and perhaps the man in Belgium, that she had moved on.

That suspicion followed the marriage ever since. But none of that was visible on the sixth of May 1960, when the two of them stood on the balcony of Buckingham Palace and waved to the cheering crowds below. For a few years afterwards it genuinely looked as if they had pulled it off. The honeymoon was spent on board the royal yacht Britannia, cruising around the Caribbean for six weeks.

One of their stops was a small, almost undeveloped island in the Grenadines called Mustique. It belonged to an eccentric aristocrat and old friend of the princess named Colin Tennant, and as a wedding present he gave her a plot of land there. Over the following years she built a villa on it, called Les Jolies Eaux, designed by her new husband’s uncle Oliver Messel. The island would become her refuge, and later the setting for the scandal that ended the marriage.

When they returned, the couple settled into life in Kensington Palace. At first Armstrong-Jones refused a title. He wanted to keep working as a photographer and did not want to be seen as a man who had married his way into the aristocracy. But in October 1961, shortly before their first child was born, he accepted the title of Earl of Snowdon.

From then on the world knew them as Princess Margaret and Lord Snowdon. Their son David was born on the third of November 1961. Their daughter, Lady Sarah, followed on the first of May 1964. For those first years they were the most glamorous couple in Britain.

It was the beginning of the 1960s, and London was about to become the most exciting city in the world: the London of the Beatles, Mary Quant, the miniskirt, Carnaby Street, and a new generation of photographers, actors, and designers who did not care about class or birth. The princess and her husband were at the very center of it. They went to theater first nights and threw parties at Kensington Palace where royalty mixed with pop stars, comedians, and film actors. The comedian Peter Sellers became a close friend.

For a while it seemed the royal family had finally joined the modern world, and it was the princess and her photographer husband who had brought them into it. Lord Snowdon kept working, and his work was often remarkable. In 1962 he became an artistic adviser to the new Sunday Times magazine, and over the years he produced serious photographic essays on subjects such as mental illness, poverty, and old age. He helped design a striking aviary for London Zoo that still stands today.

In 1969 he was put in charge of designing the investiture of Prince Charles as Prince of Wales at Caernarfon Castle, a ceremony watched by millions. But even in those early years there were signs of trouble. He was often away working. When he was at home he would disappear for hours into his darkroom.

He had a cottage in Sussex on the Nymans estate that had belonged to his mother’s family, and he spent more and more time there. She liked to stay up late and sleep late, surrounded by friends and cigarettes and whiskey. He liked to work. She was used to deference, even from her husband.

He hated being told what to do. By the middle of the 1960s the quarrels that had once looked like playful teasing were becoming something much darker. It was never a gentle marriage, but around the mid-1960s it became a cruel one. People who spent time with them described arguments that started over nothing and escalated quickly, often in front of guests.

They could both be wounding. She could be imperious and cutting, reminding him who she was. He could be cold, sarcastic, and deliberately hurtful, and he seemed to know exactly where to aim. Then there were the notes.

According to his biographers, Lord Snowdon began leaving written messages for his wife in places where he knew she would find them: tucked between the pages of the books she was reading, left among her gloves, or placed in the drawers of her desk. They were not love notes. They were lists of things he disliked about her, cruel remarks about her appearance and personality, some written specifically to wound. She would open a book in the evening looking for her place and find one waiting for her.

By this point both of them were unfaithful. Lord Snowdon had a series of relationships with other women during the marriage, some brief and some long-lasting, and his friends were not surprised. The princess, too, looked elsewhere. Around 1966 she began a relationship with a wine merchant named Anthony Barton, one of her husband’s friends and the godfather of her daughter.

It caused deep bitterness when it came to light. In 1967 she became involved with Robin Douglas-Home, a pianist and a nephew of the former prime minister Sir Alec Douglas-Home. It was a brief, intense relationship, and when it ended he was heartbroken. He had struggled with depression for a long time, and in 1968 he died in tragic circumstances.

It was a loss that deeply affected the people around him and added to the darkness of those years. Within Kensington Palace the couple began living almost separate lives, with their own friends and increasingly their own rooms. They still appeared together at official events and smiled for the cameras, but the public was getting only the smallest glimpse of what was really going on. By the early 1970s the marriage was, in private, all but over.

She was lonely, drinking more, and often unhappy. He was spending most of his time elsewhere. They remained married largely because of their children, because of her position, and because divorce in the royal family still felt almost impossible. Then, in the autumn of 1973, at a house party in Scotland, the princess met a young man seventeen years her junior.

Within three years, a single photograph of the two of them would end the marriage in front of the whole world. His name was Roddy Llewellyn, the son of Sir Harry Llewellyn, a Welsh baronet and Olympic showjumping champion. In September 1973 he was twenty-five. The princess was forty-three.

They met at a house party in the Scottish borders at Glen, the family home of her old friend Colin Tennant, the same man who had given her the land on Mustique. He was handsome, gentle, a little lost, and interested in gardening, music, and the easygoing, hippie-ish life fashionable among young people in the early 1970s. He had no career to speak of and no particular ambition. By the accounts of those who knew them, he made her laugh, looked after her, and, perhaps most importantly, did not seem to want anything from her.

After years of arguing with a husband who seemed to take pleasure in wounding her, she found him restful. Their relationship developed quickly. He began to join her at Les Jolies Eaux on Mustique, where far from London and the photographers they could relax together. He spent time at the villa, helped with the garden, and became part of her circle there.

At one point the pressure of it all seemed to overwhelm him; the attention, the secrecy, and the situation he found himself in reportedly became too much, and he fled abroad for a time before returning. The relationship survived. Friends knew, and people on the island knew, but in the mid-1970s the British press still observed a certain restraint about the private lives of senior royals. As long as there was no photograph, there was no story.

Then, in February 1976, there was a photograph. A photographer managed to take a picture of the princess and Roddy Llewellyn sitting together at a beach bar on Mustique, both in their swimming costumes. The original image reportedly included other people from their group, but it was cropped so that it showed only the two of them. On the twenty-second of February 1976 it appeared on the front page of the News of the World.

The effect was explosive. The queen’s sister, married to the Earl of Snowdon, was pictured on holiday on a tropical island with a much younger man. The story was everywhere within hours, and the palace, for the first time in the history of this marriage, would have to say something in public. What it said less than a month later would shake the royal family to its core.

On the nineteenth of March 1976, Kensington Palace issued a short statement. It announced that Princess Margaret and the Earl of Snowdon had agreed to live apart. It made clear that there were no plans for divorce proceedings. It was carefully written, formal, and brief.

But it was the first time in modern memory that the marriage of such a senior member of the royal family had publicly broken down. Much of the press turned on her with a ferocity hard to imagine now. She was portrayed as spoiled, lazy, and self-indulgent, a princess who lived on public money and spent it on holidays in the Caribbean with a younger lover. Some members of Parliament openly questioned whether the taxpayer should continue to fund her.

Lord Snowdon, by contrast, came out of it well, at least in public. When he spoke briefly to reporters around the time of the announcement he appeared visibly emotional. He said he was sad, asked people to understand, spoke with love of their children, and said he hoped they would all be happy. Many people saw a dignified, wounded husband.

The cruel notes, the arguments, and his own affairs were all unknown to the public. The photograph on the beach had shown one part of the story, and one part was all the country saw. For the princess it was a humiliating period. She was forty-five.

Newspapers followed Roddy Llewellyn relentlessly, mocking his clothes, his hair, and his attempts to launch a career as a pop singer. Cartoonists had a field day. Their two children, still young teenagers, were caught in the middle. The separation left one question hanging over everything.

The royal family had lived through the abdication of 1936 precisely because a king had wanted to marry a divorced woman. Princess Margaret had given up Peter Townsend in 1955 because he was divorced. Now, twenty years later, the princess herself was heading towards the thing she had once been told was impossible. In May 1978 the marriage was formally dissolved; the divorce became final in July 1978.

It was the first divorce so close to the throne in living memory. The queen’s own sister, the woman who had been told as a young woman that she could not marry a divorced man, was now divorced herself. The irony was lost on almost nobody. Lord Snowdon remarried quickly.

In December 1978, just months after the divorce, he married Lucy Lindsay-Hogg, with whom he had been involved for some time. Their daughter, Frances, was born the following year. The princess did not remarry. She could have, in theory, but she never did.

That same year Peter Townsend published his memoirs, in which he wrote with warmth and discretion about his time with the royal family and his feelings for the princess; people who read them sensed how much that old love had meant to both of them. He was living quietly in France with his wife and children by then. Roddy Llewellyn stayed with her for several more years, but he was much younger and wanted a family of his own. In 1981 he married a young woman named Tatiana Soskin.

By all accounts the princess took it gracefully, and they remained friends for the rest of her life. In the years that followed she carried out royal duties, supported dozens of charities, and escaped to Mustique whenever she could. She also had a reputation, fairly or not, as the difficult royal, the one who could be rude to people, who stood on ceremony, and who never quite found a place for herself. Her relationship with her former husband slowly thawed.

They were united by their children, and in later years they could be civil and even friendly with each other at family occasions. But there were more secrets still to come out about him, and in the final years of both their lives the full picture of what the marriage had really been would finally emerge. She had smoked heavily since her teenage years, and in the end her health paid the price. In January 1985 she had an operation to remove part of her left lung; the growth turned out not to be cancerous, but it was a warning.

She cut back but did not stop entirely. In February 1998, while staying at her villa on Mustique, she suffered a stroke. The following year, again on the island, she badly scalded her feet in an accident in the bath, and the injury left her unable to walk properly for a long time. More strokes followed in 2001.

By then she was often in a wheelchair, her eyesight was failing, and she was rarely seen in public. One of her last appearances was at a family celebration, where she looked frail and was partly hidden behind dark glasses. She died on the ninth of February 2002 at King Edward VII’s Hospital in London at the age of seventy-one. Her funeral took place at St George’s Chapel, Windsor, on the fifteenth of February 2002, exactly fifty years to the day after the funeral of her beloved father, King George VI.

At her own request she was cremated, which was highly unusual for a member of the royal family, and her ashes were later placed in the same chapel alongside her parents. Her mother, the Queen Mother, died less than two months later at the age of 101. Lord Snowdon attended the funeral. Peter Townsend had died years earlier, in 1995, in France.

In the early 1990s, according to those close to her, the two of them had met again privately in London for the first time in decades and had spent time talking together. What was said between them, nobody else knows. After the princess’s death, more of her former husband’s secrets surfaced. In 2004 the DNA test confirmed that Polly Fry, born weeks after the royal wedding in 1960, was his daughter.

It was also revealed that he had fathered a son, Jasper, born in 1998 to a journalist named Melanie Cable-Alexander, while he was still married to his second wife. His second marriage ended in separation. He also had a long relationship with a woman named Ann Hills that stretched over many years through both of his marriages; her death in 1996 was a very sad one, and it too became part of the story told about him in later years. Biographers later described a man who was brilliant, funny, deeply insecure, and at times capable of great cruelty to the people who loved him.

He died on the thirteenth of January 2017 at the age of eighty-six. Looking back now, it is hard to find the moment when this marriage might have been saved. She was a princess raised to expect deference. He was a man who could not stand to be owned by anyone.

She loved late nights, parties, and the familiar comforts of palace life. He loved his work, his freedom, and a world she could never really enter. They were also, in their way, very much alike. Both were clever, funny, stylish, and easily bored.

Both had grown up feeling that they came second, she to her sister, he to his mother’s new family. Both could be charming to strangers and wounding to each other. Two people like that can have a thrilling love affair. They rarely have a peaceful marriage.

And behind all of it stood the decision of 1955: the young princess told she could not marry the war hero she loved because he was divorced, only to end up divorced herself twenty-three years later. In the years after her marriage ended, the rules that had kept her from Townsend slowly began to change. Within a generation, three of her sister’s four children would also go through divorces, and the royal family would learn to live with them. But that change came too late for her.

Today the old black-and-white footage of that spring day in 1960 still looks like a fairy tale. The glass coach, the Hartnell gown, the crowds along the Mall, the tiny princess walking up the long aisle of Westminster Abbey towards the handsome young man who had made her laugh. The whole country believed it was watching a love story finally coming right.