Allan Kaprow (August 23, 1927 – April 5, 2006) was an American painter, assemblagist and a pioneer in establishing the concepts of performance art. He helped to develop the "Environment" and "Happening" in the late 1950s and 1960s, as well as their theory. His Happenings - some 200 of them - evolved over the years. Eventually Kaprow shifted his practice into what he called "Activities", intimately scaled pieces for one or several players, devoted to the study of normal human activity in a way congruent to ordinary life. Fluxus, Performance art, and Installation art was, in turn, influenced by his work.