Conversation so far:
When was the Museum created?
she created in 1918.
Who was museum named for?
Gertrude Vanderbilt Whitney.
Who was she?
Gertrude Vanderbilt Whitney, the museum's namesake and founder.
How did the museum begin?
she offered to donate over 500 works of art to the Metropolitan Museum of Art, but the museum declined the gift.

Question: What did she do when she was declined?
Self-contained rewrite: What did Gertrude Vanderbilt Whitney do when she was declined?