WASHINGTON — At the 100th anniversary of Washington's Women's Suffrage Parade on Sunday, participants will march in the bold tradition of suffragette Inez Milholland — even if they, and most of America, have never heard of her. Of all the images and people invoked during this centennial celebration, perhaps the least remembered is the one woman said to have died for the cause.

Milholland, 27, sitting astride a white horse, in white, flowing, Joan of Arc robes is the most iconic image of that 1913 march. When she died three years later, she was hailed as a martyr of the women's suffrage movement. That she is barely remembered today is part of the challenge and frustration for those who advocate for greater attention to women's history and for those trying to build a national women's history museum on the Mall.

The march, sponsored by Delta Sigma Theta sorority and including the National Women's History Museum, the Sewall-Belmont House Museum and the National Organization for Women, retraces the original 5,000-person march down Pennsylvania Avenue. It will feature women in period costumes and focus broadly on women's equality.

But in 1913, it was all about the vote.

Milholland, raised in a wealthy Brooklyn family, was educated at Vassar and had a law degree from New York University. Her father was a writer for the New York Tribune, and her parents supported progressive causes, including suffrage and civil rights. She was on the leading edge of educated women advocating for civil, labor and women's rights. She said she proposed to her husband, Dutch importer Eugen Jan Boissevain, as part of her "new freedom" as a woman.

Milholland and Alice Paul, whom history remembers as an architect of women's suffrage, organized the 1913 march, and infused it with allegory and symbolism. Justice, liberty, peace and hope were represented by women in robes and colorful scarves, accompanied by the sound of trumpets. Milholland helped wrap the broad themes of American life in canny visual appeals, including her youth and beauty at a time when suffragists were derided for being unfeminine and lacking respectability.

"The only people who have heard about her are those who majored in women's history in college," says Joan Wages, president and chief executive of the National Women's History Museum, which has been trying to secure a permanent site on the Mall for nearly 20 years. "That is because the history textbooks still say that women were 'given' the vote in 1920. The 72 years that led up to that 1920 amendment are just erased."

That Milholland is nearly forgotten underscores the need for a museum to house those images and people who helped build some of the nation's most transformative movements, Wages says. Scholars have done all this research, "but it's not making its way into the public arena, and that will be our role, to be the bridge."

On Wednesday, Reps. Carolyn B. Maloney, D-N.Y., and Marsha Blackburn, R-Tenn., and Del. Eleanor Holmes Norton, D-D.C., introduced a bill to establish a privately funded bipartisan commission to determine the feasibility of a women's history museum on the Mall.

"The history of our country, like history in general, is usually about top-ranked leaders," says Norton, who points out that legislation about the museum has been introduced for at least 10 years. "If you are writing only about leaders for a millennia, you will only be writing about men. That doesn't mean that half the population hasn't made extraordinary contributions to civilization." The proposed museum might include famous women, but its focus would be women's history, which is "mostly not made by famous women, even when that history was extraordinary."

Maloney says she'd heard of Milholland "with her white horse, marching around for suffrage movements, giving so many speeches that she fainted every time. I think people should know about her bravery."

For all their pageantry, the 1913 parade marchers were heckled and jeered mostly by men, large numbers of whom were in town for Woodrow Wilson's inauguration the next day.

"You can't win against misogynist men, but you can help a movement have courage in the face of all that," says Kathryn Kish Sklar, who specializes in the history of women's social movements at the State University of New York at Binghamton. That was a large part of what Milholland gave to the cause.

The other part was her life.

Milholland frequently traveled for speaking engagements and activist events. She suffered from pernicious anemia but wouldn't curtail her travel, despite the pleas of her family. In 1916, she collapsed in the middle of a women's rights speech in Los Angeles and died a month later. She was 30 years old. Reportedly, her last words were "Mr. President, how long must women wait for liberty?" Poems have been written about Milholland, and Julia Ormond played her in the 2004 television movie about Alice Paul and the founding of the National Women's Party, "Iron Jawed Angels."

The notion of those largely forgotten by history also strikes a chord with Sunday's march organizers. Cynthia Butler-McIntyre, president of Delta Sigma Theta Sorority Inc., says when organizers saw historical pictures from the 1913 march, they were immediately drawn to Milholland on horseback.

"That's how we found out about her role in the march," Butler-McIntyre says. There was some conversation "about doing the horse," she says, but "you have to come back to reality and stick to the true purpose of the message now." The Deltas had been incorporated at Howard University two months before the 1913 march, and its 22 founders were among the few groups of African Americans who participated.

Gwendolyn Boyd, chairwoman of the Deltas' Centennial Celebrations, says the Deltas can identify with Milholland, because in descriptions of the original march, the sorority's participation is often overlooked. "We understand how we have to continue to speak up so that our place in history is not lost or forgotten or misplaced."