Dutch pioneer of abstract art, who developed from early landscape pictures to geometric abstract works of a most rigorous kind. Born in Amersfoort, Utrecht. Studied painting at the Amsterdam Academy 1892-4 and again, part-time, 1896-7. Friendship with the painter Simon Mans and painted landscapes in the Hague School tradition. Began to work in a more vividly coloured and sometimes pointillist style in 1908, joined the Theosophic Organisation in 1909 and made some works of a Symbolist character.