Perhaps the only hitch in the day's proceedings came when band leader Eddie Drennon, fronting an ensemble of nine of the best Latin musicians in Washington, shot his hands up in the air and stopped the music.

"Wait a minute," he said. "I'm on the wrong island!"

The standing-room-only crowd in the Smithsonian's S. Dillon Ripley Center knew just what he meant -- Drennon had jumped from one style of Latin music to another, moving almost accidentally from the son music of eastern Cuba to Haitian-influenced merengue. And yet that sometimes confusing blend of geographic influences -- Cuba, the Dominican Republic, Puerto Rico, Africa, New York and even Washington -- was the very point of Saturday's gathering, a conference on the roots of Afro-Latin music in Washington. The stars of the show were local musicians, such as Drennon and the members of his pickup band, who ruled the city's club scene in the 1950s and '60s, when mambo and rumba were king.

Drennon found himself on the wrong island at an afternoon seminar that he called simply "Which Is It? Mambo, Rumba or Cha-Cha-Cha?" Backed by the ensemble and an audience of almost 200 enthusiastic questioners -- and sometimes dancers -- Drennon compressed the varied rhythms of different Latin styles into a raucous and thrilling hour. Not everyone could detect and preserve in memory the slight difference between, say, Dominican and New York merengue, but clearly everyone enjoyed trying.

Such seminars weren't necessary when Latin music was at its peak of popularity. But even while illuminating the international origins of the music, the day-long conference managed to shine light on some curiosities in Washington's own musical history. To start with, almost none of the participating musicians were Latin. Rumba music here originally belonged to African Americans, who may not have grown up speaking Spanish but did know how to capture the music of the day and make it their own.

Typical was Maria Rodriguez, a conservatory-trained pianist who became one of the only female band leaders on the D.C. scene when she headed Los Magnificos. Rodriguez can still dance a one-two rumba and sing Spanish lyrics in a high, clear voice, but she doesn't always know what the words mean. Born Jean Butler, she took "Rodriguez" as a stage name to make herself seem more authentic.

The African American roots of local Latin music were mapped by the Smithsonian's Anacostia Museum as part of its exhibit "Black Mosaic: Community, Race and Ethnicity Among Black Immigrants in Washington, D.C." Saturday's conference included an overview of local music, the "Which Is It?" demonstration and panels on the contributions of African American and immigrant musicians.

"Yes, we speak Spanish, Portuguese, French and English," said Anacostia Museum Director Steven Newsome, identifying Latin music as one component in a black cultural diaspora stretching across the New World. "It's important that this museum, this national Smithsonian, speak the vernacular," he said. "We need to move like, sound like and shake like America."

Shake they did. By the time Drennon had taken his tour of the musical horizon through Cuba, Haiti, Puerto Rico and the Dominican Republic, audience members were unable to remain in their seats. The seminar ended when Drennon led the musicians in a long and joyously disorganized salsa performance, with couples dancing in the aisle and volunteers from the audience singing backup into a microphone borrowed from the speaker's podium. All the notes fell into place for Nikki Trahan, a 23-year-old District native who came to the Smithsonian seeking a piece of her own history. "I'm so excited I could bust," she said, explaining that she had grown up surrounded by rumba, mambo and cha-cha, and was the daughter of a trumpeter who played Latin music. Later, living in New York, she was disconcerted to see that Latin music there was chiefly -- and sometimes exclusively -- an arena for Latinos.

"It's kind of hard for an American to penetrate that," she said. "But in D.C., because it has been dominated by Americans, it is more open to everyone."

Some members of an older generation of African American musicians came to the same conclusion. "Latin music," said Hedrick Mitchell, one of the pioneers of the music in Washington, "was something that was not a part of our native culture, or so we thought. But we have discovered here that Latin music has its roots in the African continent and is something I can claim as part of my roots."

Those roots spread out from Africa, through Cuba and other Caribbean islands into Washington and beyond -- way beyond.

"There was nothing ever so grand as the mambo, the rumba and the cha-cha-cha," former mambo dancer and band leader Paul Hawkins said at one point. "You could go to Japan and people would be doing the cha-cha-cha. You could go to Germany and people would be doing it."

Not to mention Vietnam. A young Vietnamese man in the audience rose to mention that Latin music had penetrated even to Saigon. While the musicians on the podium looked on in disbelief, he explained that the years when mambo was king corresponded exactly with the years of French rule in Vietnam. The Latin rhythm now blares from discos in Southeast Asia.

Like the musicians themselves, the audience for Latin music in Washington was historically not very Latin. Even after a small wave of Cubans and Dominicans settled here in the 1960s, it was still rare to see Spanish speakers at the shows, recalled Roland Kave, a veteran of several local bands. In an effort to drum up an audience, he mailed concert announcements to the few Latin names he could find in a District phone book. "I remember there were a lot of Cruzes," he said.

Kave brought a stack of his own singles to the Smithsonian event. As "Tito Valdez" he had successfully covered several standards, but Kave reduced his fellow musicians to tears of laughter when he held up his less successful attempt at crossover music, a pair of singles recorded with a rock-and-roll band and titled "El Twisto" and "I Love You So Cha Cha Cha."

Less funny was his remembrance of the segregated club scene. Even though the music on the stage embodied cross-cultural contact, the clubs themselves remained mired in Jim Crow-era rules, including a north Baltimore club where Kave was forced to enter though a side door.

"For the first time in my life, I compromised with segregation," he told a temporarily hushed audience. "I went into a segregated club for the money. I wasn't even able to associate with my white friends who came up to the stage."

But segregation had an ironic and unintended effect on at least one musician at the conference. Lloyd McNeill, a flute and bongo player who grew up in Washington, was supposed to learn classical music as a child. But because blacks were required to sit in the balcony of DAR Constitution Hall during recitals, McNeill rebelled and joined the drum and bugle corps of the Metropolitan Police Boys Club instead.

Drum and bugle corps were the base of Washington's Latin music fever. Not only did they provide the essential tools of the music -- percussion sections and brass harmonies -- but they instilled the competitive instincts that fueled the movement. Area high schools such as Cardozo and Dunbar fielded rival drum and bugle corps that fed talented young graduates into the highly competitive club scene. McNeill admitted that his first band, the Caribbeans, was formed at Dunbar in direct imitation of Hedrick Mitchell's Los Americanos, formed at Cardozo in 1951.

But the competition wasn't always quite what it seemed. Two participants, Hawkins and Julian "Julio" Miranda, were rival band leaders whose musical confrontations were a staple at clubs such as the Cairo Hotel Ballroom, the Casbah and El Lido. On Saturday, Hawkins produced an old promotional photograph of himself and Miranda taken around 1965. The black-and-white shot shows the two squared off against each other in Rock Creek Park like opposing linemen in some Latin music Super Bowl.

But Hawkins, with an arm wrapped around Miranda, explained that the hostile pose had been just that, a pose. After playing against each other in a club, he said, "His crew would go out the front door saying, Julio kicked his butt!' And my crew would go out the back door saying, Paul kicked his butt!' " "And then," Hawkins said, as Miranda collapsed in laughter, "Julio and I would walk out the side door together counting the money!" CAPTION: Julio Miranda, left, Rudy Morales and Rafael Solano are on the beat at Saturday's Smithsonian conference on the roots of Afro-Latin music in Washington. CAPTION: Students at Cardozo High School organized Los Americanos, a mambo combo, in 1951. (Photo ran in an earlier edition.)