What was Marcel Duchamp known for challenging?

Marcel Duchamp is widely recognized for his innovative approach to art that fundamentally challenged artistic conventions and the established value of traditional artwork. His work often subverted expectations and questioned the very definition of art itself. For instance, his creation of 'readymades'—ordinary, manufactured objects designated as art simply by the artist's choice—provoked discussions about authorship, creativity, and the criteria for what constitutes art. This radical departure from traditional customs, particularly regarding aesthetics and the handmade nature of art, encouraged viewers and artists to reconsider their perceptions of art’s significance and purpose. Duchamp's influence extends beyond his own pieces, as he paved the way for movements such as Dada and conceptual art, which focus on ideas over traditional artistic skill or aesthetics.