Born and bred to be the King of England, the courtly Prince of Wales was the world's most eligible bachelor, attracting adoring females wherever he ventured. Unmarried still at age 41, he was widely perceived as a charming gadabout, weak-willed and incapable of making up his mind. But when the man destined to be crowned Edward VIII came to a decision, it was a doozy.

On Dec. 11, 1936, in a radio broadcast that reached millions, the newly proclaimed King announced the unthinkable. "I have found it impossible to carry the heavy burden of responsibility and to discharge my duties as King as I would wish to do," he said, "without the help and support of the woman I love." That woman was a domineering, twice-divorced American named Wallis Simpson.

Although his wildly romantic declaration cost Edward his job and his country, for the King it seemed an even exchange. "She promised to bring into my life something that wasn't there," he explained in his 1951 autobiography. "I was convinced that with her I'd be a more creative and more useful person." Others saw the relationship differently. "She was a dominatrix type," says author Gore Vidal, "and he, having been beaten up by nannies and governesses all his life, needed a strong woman to bawl him out."

Born Bessie Wallis Warfield in 1896, the dark-haired Baltimore socialite was raised by her spirited mother, Alice, after her father died of tuberculosis when she was 5 months old. Wallis was not wealthy; at one point her mother ran a rooming house to make ends meet. And she was far from beautiful; photographer Cecil Beaton described her as "attractively ugly, une belle laide." Yet she had the gumption to push her way into the highest circles and the allure to capture two husbands—Win Spencer, a naval pilot who abused her (they divorced in 1927), and Ernest Simpson, an English-American ship broker she met in New York City. When she told her friends in 1927 that she and Ernest were going to live in England, one cautioned, "Don't fall in love with the Prince of Wales." Replied Wallis: "What would I have to lose?"

As it turned out, plenty. Not only was she not allowed to become Queen, but the royal family shunned her until her husband's death in 1972, when Queen Elizabeth finally invited Wallis to stay in Buckingham Palace. And with the abdicated Edward, now given the title Duke of Windsor, she would embark on a life of aimless partying and free-spending drifting.

Edward Albert Christian George Andrew Patrick David—David to his friends—met the object of his affection in 1930 at a party in Leicestershire. Wallis, 34, came with her husband, Ernest; the Prince, 36, was in the company of his married mistress, Thelma Furness. Wallis later recalled how she was taken with his "slightly wind-rumpled hair, the turned-up nose, and a strange, wistful, almost sad look about the eyes when his expression was in repose." The Prince, however, did not really focus on Mrs. Simpson until they met again the following year. "I was struck by the grace of her carriage and the natural dignity of her movements," he remembered. But what he admired most was her American spunk. "I am truly interested in what the British heir apparent thinks and does," she told him in 1934. "You're the only woman who has ever been interested in my job," he replied. Later he would say, "Right then I made an important discovery: that a man's relationship with a woman could also be an intellectual partnership. That was the start of my falling in love with her."

Over the next two years, the Prince entertained the Simpsons often at his country retreat, Fort Belvedere, outside London. Soon Ernest slipped into the background, and the Prince began squiring Wallis alone. "He was the open sesame to a new and glittering world," she would later reflect. "Yachts materialized; the best suites in the finest hotels were flung open; aeroplanes stood waiting.... It was like being Wallis in Wonderland." In turn, "She made him feel like a man," says actress Jane Seymour, who portrayed Wallis in a 1988 TV movie. "I heard that sexually he had needs, and that somehow she fulfilled them."

By many accounts, Wallis was content with the status quo. "She never wanted to marry him," says Gore Vidal. "She had in mind being a royal mistress." But after King George V died on Jan. 20, 1936, Edward VIII reigned for just 325 days. During that time, he orchestrated Wallis's divorce. When it came through, Prime Minister Stanley Baldwin forced him to choose marriage or the monarchy. (The King, as head of the Church of England, is forbidden to marry a divorcée.) "The throne," said Edward, "means nothing to me without Wallis beside me." His brother, father of the current Queen, was crowned George VI five months later.

By this time, Wallis Simpson "was bloody bored with the King and wanted out," suggests Donald Spoto, author of the new book The Decline and Fall of the House of Windsor. "But he threatened to commit suicide, and she was cornered." They married six months later in a borrowed château in the Loire Valley before only 16 guests. She wore a pale-blue dress by famed designer Mainbocher that would be much copied. The next morning, Wallis told Gore Vidal, she woke up to find her husband "standing beside the bed, saying, 'And now what shall we do?' "

The life that followed was empty indeed. Though she was allowed to call herself the Duchess of Windsor, Wallis was denied the Royal Highness title bestowed upon her husband. "He intended to devote his life with me to mending the hurt as best he could," said Wallis of the snubbing. He did it by submitting to her every command. "The last time I saw them," recalls Gore Vidal, "she suddenly said, 'Pull up your socks, David.' He said, 'Yes, dear,' very meekly. That was the tone of their marriage."

The couple lived in voluntary exile in Paris, where they were known for their elegant dinner parties. "You have no idea how hard it is to live out a great romance," Wallis told a friend. Toward the end of their lives, they became increasingly isolated. He died at age 77; she outlived him by 14 years. "Were there regrets?" muses Gore Vidal. "There were lots of them, on both sides." And yet, having altered the course of history, they would be remembered for love, and love alone. "Nobody," says their friend C.Z. Guest, "has ever given up what he did for a woman."