The American Federation of Musicians was founded in 1896, at which time it took over from an older and looser organization of local musicians unions, the National League of Musicians.
One of the most famous actions by the AFM was a ban on all commercial recording by members in the 1940s in order to presure record companies to make a better arrangement for paying royalties to recording artists. This was sometimes called the Petrillo Ban, after the longtime powerfull leader of the Union, James Petrillo.