The year was 1938; Roumania's dowager Queen Marie lay in state surrounded by red flowers. In Bucharest, lavender flags and bunting floated from windows along the route of the cortege, where 250,000 people gathered to pay their last respects. The Queen's mourners were requested to dress not in black, but in mauve, her favorite color. Among them were her children: Roumania's King Carol II, Yugoslavia's Queen Mother Marie and Greece's ex-Queen Elizabeth. The Bucharest Symphony provided majestic exit music from Wagner's Götterdämmerung. She did have style.

So who was Marie of Roumania, and what did she do to deserve this send-off? Although practically forgotten now, she was, from World War I until her death, one of the world's most celebrated royals—the Princess Di of her day. At the time of World War I, this English-bred granddaughter of Queen Victoria counted among her first cousins England's King George V, Kaiser Wilhelm II, Czar Nicholas II and his wife, Alexandra—not to mention the queens of Norway, Spain and Greece. Marie dictated fashion, wrote Roumanian fairy tales, was idolized by men and gave outspoken interviews on equality for women that shocked her noble relatives. When she visited the U.S. in 1926, she scandalized the White House by wearing a knee-length gown to visit President Coolidge. Vain? Unbelievably so. She once penned a note to herself that read: "Marie of Roumania—one of the most wonderful women in the world. A woman like that is born once in a century."

But Marie wasn't a frivolous figurehead. Politically astute, she gallantly led her adopted country through World War I, famine and a typhus epidemic. "Every man was in love with her," wrote romantic novelist Lesley Blanch, "every artist inspired by her; every woman wished to look like her."

For the past decade Hannah Pakula, 51, wife of film director Alan (Sophie's Choice) Pakula, has been obsessed with Queen Marie's life. The result is a hefty biography, titled The Last Romantic: A Biography of Queen Marie of Roumania (Simon and Schuster, $19.95).

Pakula first became intrigued with Marie in high school, when she tried to translate into French a short Dorothy Parker poem that immortalizes Marie as the ultimate fantasy figure. That poem, which introduces Pakula's book, proclaims:

Oh, life is a glorious cycle of song,
A medley of extemporanea;
And love is a thing that can never go wrong;
And I am Marie of Roumania.

Then in 1975 Pakula read novelist Blanch's Pavillions of the Heart, in which the author describes one of Marie's ornate palaces. That did it. "I went to the library and took out everything I could on her," Pakula says. "I decided there was room for a major book. I had to know who Marie was, and why she disappeared from history."

For the late-blooming, first-time author, the biography also proved to be a voyage of self-discovery. "Writing it was quite a journey for Hannah," says Alan, who married her 12 years ago after his divorce from actress Hope Lange. "As Hannah was learning about Marie—how she went from a naive princess to a political force in her country—my wife was discovering her own worth as a scholar and writer." At first, Alan, who was shooting All the President's Men when Hannah began her book, was dubious about his wife's project. Six months later he read the first chapter on a plane to Washington, D.C. "I waited until I was away to read it," he admits. "I called Hannah and said, 'It's terrific!' She said, 'You sound surprised.' I said, 'No, just relieved.' "

The blond, striking author was reared in Beverly Hills, where she attended Westlake School for Girls, which numbers Shirley Temple Black and Sally Ride among its classy alumnae. From Westlake, Hannah went on to attend Wellesley, the Sorbonne and Southern Methodist University. At the Sorbonne Hannah married her first husband, investment adviser Robert L. Boorstin. After she graduated from SMU with a B.A. in comparative literature, they had three children: Anna, now 27, a sound-effects editor in Hollywood; Robert, 25, a journalist in New York; and his twin, Louis, an economist working with the Save the Children Federation in Africa. Boorstin died of a heart attack in 1969. In 1970, Hannah met Pakula at a dinner party in New York City. Alan waited five months to call her, "because I knew it was going to be serious." They married in 1973. Six years later they moved from L.A. to New York because Alan missed the energy of his hometown. They now inhabit a lavish Park Avenue apartment where the luxury-loving Queen Marie would have felt right at home.

In the course of her research for The Last Romantic, Hannah became close friends with Ileana, 75, Marie's youngest daughter and only surviving child. A former princess of Roumania who divorced an Austrian archduke, Ileana lives in Pennsylvania, where she is the Rev. Mother Alexandra, an Eastern Orthodox nun. It was through Ileana that Hannah learned of Marie's diaries, which had been sealed away somewhere in Bucharest.

"For years I wrote to the Roumanian government trying to gain access to those diaries," Pakula says. Then in 1982, while Alan was cutting Sophie's Choice, Hannah and a friend, short-story writer Barbara Thompson Davis, journeyed to Roumania. "I hadn't been there before and wanted to improve my physical descriptions of the places I was writing about," Hannah says. On her first afternoon in Bucharest she got a royal surprise. The American cultural attaché told her that she was invited to visit the historical archives and to see the diaries. "I still don't understand why that happened," Pakula says. "In Roumania, Marie's name is never mentioned outside the archives. Young people don't know who she is. Because this is a Communist country, old people are hesitant about discussing the contributions of a previous regime."

As if seeing the diaries weren't enough, Pakula got a bonus—1,200 of Marie's letters. "Letters that nobody had ever seen before," she says. "Letters from George V, when he was a young sailor who wanted to marry Marie; magnificent letters, in French, from Prince Barbo Stirbey, the great love of Marie's life; letters to and from her mother, the only daughter of Czar Alexander II of Russia; letters from King Carol II, her son, who tried to destroy her reputation and who abdicated the succession to the throne twice for two different women." Pakula and Davis remained in Bucharest for about six weeks, poring over this bounty. "I knew then," says Pakula, "that I had uncovered the answer to the riddle, who is Queen Marie of Roumania?"

The Last Romantic is dedicated: To Alan, who makes everything possible. Hannah says, "I couldn't have written this book without his saying it's okay to take chances. At first I didn't tell anyone I was writing it. Only Alan."

Now that she's found her métier, Hannah is planning two more biographies of royal figures who she won't name. "When we got married, it was I who was fascinated by history," says Alan. "Now she's the historian. It was marvelous to fall in love with a woman you thought you knew, then find out this whole other aspect of her life. I was thrilled with what I had before, but more thrilled with what I've got now." So Marie isn't the last romantic after all.