When the International Sweethearts of Rhythm sit down to tell their stories from the 1930s and ’40s, they don’t talk about the glamour of their album covers. Instead they recall the joy but also the hard work and prejudices of those times.

The Sweethearts, the nation’s first all-female integrated big band, was primarily an African American ensemble but recruited musicians of all races and nationalities, including Asian Americans and Native Americans. Rosalind Cron, a white woman who joined the group in 1943, now nearly 86 and dressed in a sharp pinstriped suit, held her audience spellbound Wednesday as she described a racial incident in El Paso. She was always the last to pack her saxophone, and that night a black soldier volunteered to escort her to catch up with her band mates. “There was a car circulating the street with two sheriffs. The car stopped and one got out,” Cron said. The two were taken to jail and the soldier told to get out of town. Cron stayed in jail all night until the Sweethearts’ chaperone came to get her out.

“I will never forget the stories of those women in the cell. It was a night I will never forget,” Cron said, adding that she had been to the El Paso airport once since then but had vowed never to step foot in the city.

Her friends of almost 70 years, seated with her on a stage at the National Museum of American History, nodded because it was a night they also wouldn’t forget. The group originated to raise funds for the Piney Woods School in rural Mississippi in 1937. “That was our foundation. We were taught to tap, do high kicks and splits, everything the Rockettes were doing,” said Lillie Keeler Sims, a trombone player, now 87.

The core group numbered 18. The band ended up being a sensation in the big-band era with tours of the States and war-torn Europe before they disbanded in 1949.

They traveled in a bus built by the Piney Woods students. “The bus was fully equipped like a home. We used to do one-nighters and play Washington, D.C., one night and the next night Baltimore or Philadelphia,” said Sadye Pankey Moore, a trumpet player who is now 87 .

But at places such as Washington’s Howard Theatre, where the all-day programs were movies and live performances, their swing band started as early as 11 a.m. “There would be a film, then we would play a set. On those days, we were the house band for the more famous people who would perform,” said Moore.

Helen Jones Woods, a trombone player now 87, interjected that some performers refused the Sweethearts’ backup. “We weren’t good enough for Sarah Vaughan. They told her the Sweethearts were playing, and she said, ‘Not while I’m living,’ and she was right,” said Woods, the mother of media businesswoman Cathy Hughes. Hughes moderated the panel along with producer and author Sally Placksin.

The Sweethearts donated artifacts from their tours to the Smithsonian as part of Jazz Appreciation Month, which is dedicating many of its programs in April to female pioneers in jazz.