Piet Mondrian, one of the founders of the Dutch modern movement De Stijl, is recognised for the purity of his abstractions and methodical practice by which he arrived at them. He radically simplified the elements of his paintings to reflect what he saw as the spiritual order underlying the visible world, creating a clear, universal aesthetic language within his canvases. In his best known paintings from the 1920s, Mondrian reduced his shapes to lines and rectangles and his palette to fundamental basics pushing past references to the outside world toward pure abstraction.