William Alvin Moncrief Jr., a Texas wildcatter who helped build a father-son venture into an oil and gas empire over more than 70 years in the industry, has died. He was 101.

A spokeswoman for Moncrief Oil confirmed his death to The Associated Press Wednesday but could not immediately provide further details.

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Moncrief, who went by the nickname “Tex,” was born in Arkansas in 1920 on his family’s kitchen table, according to Texas Monthly. His father, William Alvin “Monty” Moncrief, was among the early wildcatters to drill for oil in East Texas.

The younger Moncrief spent his life building on that tradition, acquiring a fortune that earned him a reputation as a generous philanthropist but also attracted scrutiny from tax authorities.

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At the age of 10, Moncrief witnessed his father open a “gusher” oil well in Greggton, 128 miles (206 kilometers) east of Dallas. People had gathered to watch the drilling and were initially disappointed when the well pushed up only muddy water, the younger Moncrief told the Longview News-Journal last year.

But then “it shot out about 90 to 100 feet,” he recalled. “When it shot out 100 feet, it made solid oil.”

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As a young man, Moncrief considered quitting school to pursue golf professionally. But his father talked him out of it and he graduated from the University of Texas in 1942 with a degree in petroleum engineering.

After the United States entered World War II, Moncrief enlisted and served as a naval officer in the Pacific. Upon returning to Texas, he went into business with his father and the pair acquired major oil and gas prospects across the country.

“The Moncriefs have been synonymous with Texas oil and big finds for a long time,” Bruce Bullock, director of the Maguire Energy Institute at Southern Methodist University in Dallas, told the Fort Worth Star-Telegram in 2015.

Forbes magazine named Moncrief to its billionaires list in 2006 and listed his net worth as $1 billion in 2014, writing that the biggest find of his career came four years earlier with the discovery of the deep-water gas reserves off the coast of Louisiana that became known as the “Davy Jones” field.

In 1994, Moncrief’s wealth attracted the attention of tax authorities. Internal Revenue Service agents raided his Fort Worth offices and later accused his family and company of bilking the government out of more than $100 million in taxes. Moncrief eventually pleaded no contest to a tax suit, paying the IRS $23 million but decrying the agency’s aggressive tactics.

Moncrief was a major donor to Texas Christian University, University of Texas, and the UT Southwestern Medical Center, where a Fort Worth medical complex and cancer center are named for him. He also served on the University of Texas System board of regents.

State Rep. Charlie Geren, a Fort Worth Republican, said Moncrief’s philanthropy improved many lives.

“He was an incredibly generous man and a real legend in the Texas oil and gas industry,” Geren said.