The Godfather of Performance Art

Bruce Nauman's Waling in an Exaggerated Manner Around the Perimeter of a Square (1967-8) is a seminal piece of performance work which has inspired many artists in the twenty-first century. He is an artist that pushed the boundaries of art- especially in his early practice- to a level that had not yet been reached. a quote of his which I believe justifies as well as describes his practice is as follows,

If I was an artist and I was in the studio, then whatever I was doing in the studio must be art. At this point art became more of an activity and less of a product. http://www.art21.org/artists/bruce-nauman