[1][2] Emerging in the 16th and 17th centuries, Gnawa music developed through the cultural fusion of West Africans brought to Morocco, notably the Hausa, Fulani, and Bambara peoples, whose presence and heritage are reflected in the songs and rituals.

Though many of the influences that formed this music can be traced to West African kingdoms, its traditional practice is concentrated in Morocco.

The large, heavy iron castanets known as qraqab or krakeb and a three-string lute known as a hajhuj, guembri or gimbri, or sentir, are central to Gnawa music.

[7] The hajhuj has strong historical and musical links to West African lutes like the Hausa halam, a direct ancestor of the banjo.

Gnawa hajhuj players use a technique which 19th century American minstrel banjo instruction manuals identify as "brushless drop-thumb frailing".

The derdeba is jointly animated by a maâlem (master musician) at the head of his troop and by a moqadma or shuwafa (clairvoyant) who is in charge of the accessories and clothing necessary to the ritual.

Meanwhile, the maâlem, using the guembri and by burning incense, calls the saints and the supernatural entities to present themselves in order to take possession of the followers, who devote themselves to ecstatic dancing.

Preceded by an animal sacrifice that assures the presence of the spirits, the all-night ritual begins with an opening that consecrates the space, the aâda ("habit" or traditional norm; Arabic: عادة), during which the musicians perform a swirling acrobatic dance while playing the krakeb.

These entities, treated like "presences" (called hadra, Arabic: حضرة) that the consciousness meets in ecstatic space and time, are related to mental complexes, human characters, and behaviors.

The aim of the ritual is to reintegrate and to balance the main powers of the human body, made by the same energy that supports the perceptible phenomena and divine creative activity.

Later, the guembri opens the treq ("path," Arabic: طريق), the strictly encoded sequence of the ritual repertoire of music, dances, colors and incenses, that guides in the ecstatic trip across the realms of the seven mluk, until the renaissance in the common world, at the first lights of dawn.

Past participants have included Randy Weston, Adam Rudolph, The Wailers, Pharoah Sanders, Keziah Jones, Byron Wallen, Omar Sosa, Doudou N'Diaye Rose, and the Italian trumpet player Paolo Fresu.

These groups offer a rich mix of musical and cultural backgrounds, fusing their individual influences into a collective sound.