LOS ANGELES – Phoebe Hearst Cooke, a granddaughter of publishing tycoon William Randolph Hearst who used one of the nation’s biggest fortunes to support a variety of philanthropic causes, died Sunday in a Templeton, Calif., hospital of pneumonia, according to the Hearst Corp. She was 85.

A fixture on the Forbes list of the 400 wealthiest Americans, Cooke had personal assets recently estimated by the magazine at $1.9 billion.

Although her flamboyant grandfather built a newspaper dynasty, Cooke was not a particularly public figure. An ardent horsewoman, she was best known as a rancher who gave extensively to equestrian organizations. She retired from the Hearst board in 1998.

Cooke was born July 13, 1927, in San Francisco to George Randolph Hearst and his wife, Blanche. Her father was a Hearst executive and the eldest of five sons of William Randolph Hearst, who was known as W.R. to a family that included 15 grandchildren..

Spending time as a child on Hearst’s vast ranch and the family’s other Central Coast properties, Cooke was steeped in Western traditions and became an avid rider.

A former California horse racing commissioner, she was inducted into the National Cowboy & Western Heritage Museum’s Hall of Fame in 1996, along with her husband, Amory J. “Jack” Cooke, who managed the Hearst family’s ranching operations.

She also was active in the National Center for Equine Facilitated Therapy, a facility she helped found in Woodside, the upscale San Francisco Bay Area community where she and her husband lived for much of their 45-year marriage.

Her husband died in 2008. Cooke is survived by Phoebe “Misty” Tovrea Lipari, her daughter with her first husband, Phillip Tovrea Jr., and a grandson.