De Stijl was a Dutch artistic movement founded in 1917 that advocated for pure abstraction through geometric forms and limited primary colors. Key members included Piet Mondrian, Theo van Doesburg, Gerrit Rietveld, and J.J.P. Oud. They sought to achieve spiritual harmony and order through compositions of horizontal and vertical black, white, and primary color planes. Rietveld's Schröder House from 1924 was the only building constructed fully according to De Stijl principles. De Stijl had a lasting influence on architecture through its emphasis on simplified forms and use of primary colors.