Successful investor, Republican donor and onetime Wyoming governor candidate Foster Friess passed away at the age of 81 on Thursday.

"We are grateful for the wonderful life Foster lived and thankful to the many people who have shared their prayers during his illness. We know many of you mourn with us, and we will have more details soon on Foster's funeral," Friess's family said in a statement.

Friess is survived by his wife Lynnette, their four children and fifteen grandchildren. He is best known as both an investor and Republican donor, funding Rick Santorum's 2012 presidential campaign as well as investing in conservative news site The Daily Caller. Friess was also a well-known philanthropist said to have given away over $500 million.

Friess said in March that he was battling myelodysplastic syndrome, a cancer that affects the bone marrow.

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Born in Rice Lake, Wisc., he later called Wyoming home and ran for governor there in 2018, being defeated in the Republican primary by Wyoming's current governor Mark Gordon.

Remembrances of Friess poured in on social media.

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"Sad to hear today of the passing of my friend, Foster Friess. A true Patriot, a generous philanthropist, and a good person who always had a kind and encouraging word. His accomplishments are many, and he will be missed," Sen. Rand Paul, R-Ky., wrote on Twitter. 

"The conservative movement lost a great friend today. Foster Friess was a generous supporter of so many causes including my beloved Log Cabin GOP. I was honored by his generosity to me and us - and grateful for his American spirit. RIP Foster," former ambassador Ric Grenell wrote on Twitter.

This story is developing and will be updated.