Jean Piaget (1896 - 1980) was a Swiss philosopher, natural scientist and developmental theorist, well known for his work studying children, his theory of cognitive development, and his epistemological view called "genetic epistemology." In 1955, he created the International Centre for Genetic Epistemology in Geneva and directed it until his death in 1980. According to Ernst von Glasersfeld, Jean Piaget was "the great pioneer of the constructivist theory of knowing."