Pieter Cornelis "Piet" Mondriaan, after 1906 Mondrian, was a Dutch painter. Mondrian was a contributor to the De Stijl art movement and group, which was founded by Theo van Doesburg. He evolved a non-representational form which he termed neoplasticism. This consisted of white ground, upon which he painted a grid of vertical and horizontal black lines and the three primary colors. Mondrian’s arrival in Paris from the Netherlands in 1911 marked the beginning of a period of profound change. He encountered experiments in Cubism and with the intent of integrating himself within the Parisian avant-garde removed an « a » from the Dutch spelling of his name (Mondriaan).