The historian Sylviane Diouf and ethnomusicologist Gerhard Kubik identify Islamic music as an influence on field holler music.[20][21] Diouf notes a striking resemblance between the Islamic call to prayer (originating from Bilal ibn Rabah, a famous Abyssinian African Muslim in the early 7th century) and 19th-century field holler music, noting that both have similar lyrics praising God, melody, note changes, "words that seem to quiver and shake" in the vocal chords, dramatic changes in musical scales, and nasal intonation. She attributes the origins of field holler music to African Muslim slaves who accounted for an estimated 30% of African slaves in America.