Marion grew up on Four Sixes Ranch in King County, Texas – famed for its cattle, horses and oil discoveries.
She married four times and her husband for the last 32 years of her life was Sotheby’s chairman and auctioneer John L Marion.
Anne donated many works to museums, and oversaw, through her charitable foundation, the distribution of more than $600m worth of grants to a variety of institutions and causes. She helped support and was either a board member or trustee of many museums over the years, including the Kimbell Art Museum, the Museum of Modern Art in New York and Modern Art Museum of Fort Worth.
With her husband she founded the USA’s first museum dedicated to a female artist - Georgia O'Keeffe - in Santa Fe.
Her collection was focused on American Post-war art and carries an estimate of $150m, but it also includes Old Masters and jewellery.
The top lots are expected to be works by Andy Warhol, Richard Diebenkorn and Clyfford Still.
The collection will be offered in a series of sales at Sotheby’s New York beginning with an 18-lot dedicated evening auction in May.
Amy Cappellazzo, chairman of Sotheby’s global fine arts division, said: “Anne Marion was a true art collector and had an eye for quality. She was brave in everything she did, from her choice in artwork to her sense of design and colour. Unpretentious and proud of her rancher legacy and lifestyle, Anne was a bol-hearted Texan through-and-through.”
Highlights from the Collection of An American Visionary will be exhibited in a number of locations in the US from March 10 and then in Taipei and Hong Kong in April followed by London (April 14-19), and then in Sotheby’s East Hampton location before returning to Sotheby’s York Avenue gallery for a pre-sale exhibition.