A quartet is a musical composition or ensemble of four voices or instruments. Quartets originated in the mid 1800s, as an outgrowth of the African American university singing movement. They were originally known as jubilee quartets because of the nature of their repertoire and characteristics of their performance style. The quartet expresses cultural values and aesthetics of the African American community. Consisting of a four-part harmony, characteristics of quartets include a minimum of four voices, and a maximum of six. The sound is vibrant and dynamic with limited instrumentation made up of the guitar, bass, and drums. Quartets grew and gained popularity as they were featured on the radio. Money was made from quartets as they were featured in radio advertisements. Quartet members performed in tuxedos, which was not very common for black men. Important performers include the Fairfield Four and the Zion Harmonizers of New Orleans, LA. Between 1910 and 1920 over 1 million Blacks migrated from the south to the north in search of an opportunity to improve their economic and social condition. Quartets began to tour outside of their home communities as professionals or semi-professionals. Quartets are currently being incorporated into the musicals. Quartet traditions have also been featured on Broadway. In the early twentieth century, the quartet evolved into a sub-genre of gospel music. Overall Jubilee Quartets were popular African-American musical groups who influenced black religious ensembles.