[2] He emigrated to the United States in 1935, he established his own art gallery in New York City.
[1] His clients included institutions like the Museum of Fine Arts in Boston, to whom he sold Time Unveiling Truth by Giovanni Battista Tiepolo in 1961.
[4] According to The New York Times, it became "one of the finest collections of Old Master paintings and drawings in private hands.
[1] A painting by Hans Baldung Grien that Heinemann had donated to the Zimmerli Art Museum at Rutgers University in New Brunswick, N.J., had to be restituted to the Goodman/Gutmann family when it was found to have been looted by Nazis from Fritz Gutmann, a Jewish collector murdered in the Holocaust.
[5][6] In 2015, an El Greco painting which had passed through Heinemann's Pinakos Gallery, Portrait of a Gentleman, was restituted to the heirs of Julius Priester, after the painting's false provenance was discovered to conceal Nazi looting of the Priester collection.