Correction: An earlier version of this story mistakenly said former congresswoman Barbara Jordan was the first black woman elected to Congress.

Sorors of the Delta Sigma Theta participate in a church service for the stained glass reception at Howard University's Rankin Chapel in Washington, D.C. on July 11, 2013. Delta Sigma Theta, the country's largest African-American women's organization, celebrates its 100th anniversary. (Marvin Joseph/The Washington Post)

A sea of crimson and cream filled the Mall on Friday as thousands gathered for Delta Sigma Theta’s 51st national convention, which opened with the lighting of the Delta torch.

Celebrations commemorating the 100-year anniversary of the sorority included a step show on Friday and more: an ecumenical service, a social-action luncheon, a sisterhood luncheon, a gospel concert and the dedication of a stained-glass window — depicting African American women — at Howard University’s Andrew Rankin Memorial Chapel.

“We are celebrating 100 years of sisterhood, 100 years of fighting for women’s rights, 100 years of fighting for civil rights,” said Cynthia Butler-McIntyre, national president of Delta Sigma Theta, whose theme is “A sisterhood called to serve.”

“If you see us smiling, we are smiling . . . because we are members of the greatest sisterhood,” Butler-McIntyre said during the dedication at Rankin Chapel. “We enjoy being Deltas. We work hard, we work hard because we were charged with this back when the 22” founders “started here” at Howard University, “to do our part to leave our footprint on this world. We transform lives. We impact communities. That’s who we are.”

Famous members of the sorority include Betty Shabazz, the widow of Malcolm X; civil rights activist Fannie Lou Hamer; human rights activist Mary McLeod Bethune; actress Ruby Dee; singers Roberta Flack and Aretha Franklin; economist Julianne Malveaux; Johnnetta B. Cole, director of the Smithsonian’s National Museum of African Art; and congresswomen Shirley Chisholm and Barbara Jordan.

Chisholm, a New York Democrat, was the first black woman elected to Congress. Jordan, also a Democrat, was the first African American after the Reconstruction era to be elected to the Texas Senate and the first black woman from a Southern state elected to the U.S. House.

Delta Sigma Theta was founded on Jan. 13, 1913, by 22 women at Howard.

In Prince George’s County, home to the world’s largest chapter of Delta Sigma Theta, a number of high-ranking officials and county residents are members of the sorority.

Among them are Maryland Del. Carolyn J.B. Howard; Maryland State Superintendent of Schools Lillian M. Lowery; Artis G. Hampshire-Cowan, senior vice president of Howard University; and Angela D. Alsobrooks, the county’s state’s attorney.