Since the 1940's, John Latham has initiated a wide range of art movements beginning with a least-mark approach to form. This led to a shift, from conventional spatial thinking to an event based frame of reference since called assemblage, performance, structural film and video, installation, and the idea of context as half the work. A new term, "Incidental Person" or "IP," was coined to replace the word artist. The IP gained a professional status in a 'Treaty' negotiated between the artists of Artist Placement Group and the UK government in Whitehall. This has led to a number of IP associations with government departments in Europe.