As a taproot of jazz, Congo Square has a hallowed place in American history and the annals of the city. The Sunday ring dances by slaves extended the memory of an African mother culture through the shuffling, counter-clockwise patterns, set to the percussive rhythms of a replanted instrumental family. They danced amid an open-air market on a grassy plain behind ramparts to the town. From the 1740s until the Civil War, the men and women who gathered in the green expanse, now encompassed by Louis Armstrong Park, “rocked the city with their Congo dances,” as one visitor memorably noted.

In a new book from UL Press, Congo Square: African Roots in New Orleans, Freddi Williams Evans, an independent scholar and author of books for children, pinpoints the rhythmic ties with African idioms such as the habanera of Cuba and dance-and-drum music in other Caribbean islands. She writes of “the impact of the gatherings in Congo Square on the perpetuation of those rhythms … The long-term repeated performances and practices by the masses passed from and through descendants contributed to the viability of the New Orleans street beat.” The beat carried down generations as the second-line, in the poly-rhythms of people parading for funerals, Carnival parades or social aid and pleasure club events.

Evans goes deeper than any historian yet in excavating the story of Congo Square, how the Africans created a cultural memory through the music, human rhythms and in what they wore. Some of the men were “clad in either a cotton shirt, tattered and torn pantaloons, or only a sash,” she writes, while others “wore Turkish turbans of various colors including red, yellow, blue, green and brown.” Women who worked as domestic servants “commonly wore white aprons over their dresses … Many free women of color, some of whom appeared to be white, adorned their hair with colorful feathers and other accessories.”

Evans orchestrates the citations of eyewitness accounts in demonstrating how a public culture evolved. Despite recurrent efforts by white authorities to limit the spectacles, slaves began dancing in taverns run by free people of color. As more and more white people gathered on the margins of Congo Square, it became a venue. In 1846, a self-appointed master of ceremonies “operated his post dressed in a blue and white mixed suit with a black vest.

His accessories included a pair of earrings and a large silver chain that hung from his vest … [and] a white hat around which he twisted a piece of black crepe. The businessman organized his own dance circle and surrounded it with posts and ropes to keep out uninvited and ordinary dancers. He admitted only the most distinguished dancers into his ‘magic ring.’”

Evans analyzes the dance styles, songs and musical instruments on grounding the tradition as part of an African market culture. She also contributes an eloquent essay to the totemic catalog, “Ancestors of Congo Square,” as part of the New Orleans Museum of Art exhibition on African art that runs through July 17. Curated by William A. Fagaly, NOMA’s esteemed authority on ethnographic art, the carved masks, musical instruments and iconographic objects displayed in this impressive exhibition all but shimmer with rhythms.

The beaded cloth work in a Yoruba ceremonial sword and sheath share vivid properties with the beadwork patterns of Mardi Gras Indian suits. As Fagaly writes in an introductory essay: “The over-century-old tradition among African-American males of ‘suiting’ on New Orleans’ Mardi Gras day in elaborate handmade costumes of their own design ranks among the city’s extraordinary artistic achievements.”

The beaded Yoruba sheath is one of many objects in the NOMA exhibition that came from the Davis Gallery, either directly or as donations from collectors who have been clients of Charles and Kent Davis. The gallery’s long association with outlets in several West African countries has established an ethnographic legacy, marked by age and rarity, helping to make NOMA a leading space for African art in America.

Many of the eyewitness accounts of slave dances and their instrumentation were written by people who considered them savages; they wrote pejorative, at times racist, accounts nevertheless providing descriptive details that served the aims of more enlightened writers, starting with George Washington Cable in 1886. Following in that line, Freddi Williams Evans draws on the 1810 diary of architect Benjamin Latrobe, who described a cylinder-shaped drum. “The drummer straddled it while playing with his hands and fingers,” she writes in the NOMA catalog. “This style of drumming also originated among people of Kongo-Angola heritage … In Haiti, the drum played in this manner, called the juba or martinique, was a variation of the pétro drum, which accompanied religious and secular Congo dances.”