Theo van Doesburg was a Dutch painter, architect, and one of the founding members of the De Stijl movement, alongside Piet Mondrian, with whom he developed the theory of Neoplasticism, advocating for the use of geometric forms and primary colors to achieve harmony and universal beauty. His work extended beyond painting into architecture and design, reflecting his belief in the integration of art into everyday life. His art played a significant role in shaping modern abstract and minimalist art.