Final answer:
Robert Venturi spearheaded the postmodernism movement in architecture, breaking away from minimalist and stark modernist designs by adding ornamentation and historical references.
Step-by-step explanation:
In the 1960s, Robert Venturi pioneered the eclectic style of architecture called postmodernism. This architectural movement is characterized by a departure from the austerity and minimalism of Modernist architecture, integrating ornaments and playful forms that often reference different historical periods. Postmodernism in architecture rejects the functionalist limitations of Modernism by embracing complexity and contradiction, and it continuously adapts and applies past styles to new forms.