“Mr. Williams was dancing with the Martha Graham Dance Company when he was recruited by the choreographer Alvin Ailey as a last-minute replacement for an Ailey troupe member in 1963. He performed with the Alvin Ailey American Dance Theater until 2005, continued to dance with Paradigm, a trio of older dancers he formed with Carmen de Lavallade and Gus Solomons Jr., and taught at the Ailey School, on West 55th Street in Manhattan, until he died.”