Consisting of over 600 pieces, Esther Grether’s collection of 20th-century art included works by Pablo Picasso, Paul Cézanne, Salvador Dalí, and Francis Bacon.

The couple’s collection contained over 700 works including masterpieces of late 19th- and early 20th-century French paintings.

Dealer Leo Castelli embraced emerging movements like Pop (Roy Lichtenstein, James Rosenquist, Andy Warhol), Minimalism (Richard Serra, Donald Judd, Frank Stella), and Conceptual (Lawrence Weiner, Bruce Nauman, Joseph Kosuth). The Whitney Museum’s former director, David A. Ross. once said that, “Wherever the important work was in postwar American art, Leo has been at the center of it.”