William P. Foster, credited with innovating a much-imitated high-stepping style as founder and longtime director of the Florida A&M Marching 100 band, died Saturday. He was 91. Foster died in Tallahassee, university officials said. They did not release a cause of death. Foster also served as the marching band’s director from 1946 until his retirement in 1998. He created more than 200 half-time pageants for the band at the historically black university. Foster is credited with innovating marching band techniques, including a high stepping style imitated by high school and college bands nationwide.