De Stijl (The Style) was an avant-garde artistic group founded in the Netherlands in 1917. The name was also applied to a journal used to propagate the group’s theories and published between 1917 and 1932. Led by the painters Theo Van Doesburg and Piet Mondrian, the group developed an abstract, elemental style based upon primary colors, geometric planes and right angles. Pursuing spiritual harmony based upon mathematical order, De Stijl formulated a universal language of pure form and color. This became paradigmatic of modernist visual art and design.

In 1915 the painter and theorist Theo van Doesburg encountered the work of Piet Mondrian, who had developed a visual style consisting of primary colors and asymmetrical, orthogonal grids. Mondrian was inspired by the mystical ideas of the Theosophists, particularly the eccentric mathematician M.H.J. Schoenmaekers, who devised a Neo-Platonic philosophy based upon pure geometric form. Influenced by Schoenmaekers’ publications The New Image of the World (1915) and Principles of Plastic Mathematics (1916), Mondrian developed an artistic philosophy known as Neo-Plasticism (Nieuwe Beelding):

This new plastic idea will ignore the particulars of appearance, that is to say, natural form and colour. On the contrary, it should find its expression in the abstraction of form and colour, that is to say, in the straight line and the clearly defined primary colour … [This art allows] only primary colors and non-colours, only squares and rectangles, only straight and horizontal or vertical line.