Lou Brock, the left fielder for the St. Louis Cardinals who began his 19-year Major League Baseball career with the 1961 Chicago Cubs, passed away on Sunday at the age of 81.

Brock’s agent, Dick Zitzmann, confirmed his death to The Associated Press. However, he did not provide any details.

In 2017, Brock started receiving treatment for multiple myeloma, a cancer that forms in a type of white blood cell known as a plasma cell. In 2015, he had to get his left leg amputated due to infection related to diabetes.

Cardinals manager Johnny Keane sought Brock for his largely untapped speed. He helped take St. Louis to the 1964 World Series championship, turning around games year after year with his feet and his bat.

Brock led the National League in steals eight times, helping propel the Cardinals to three pennants and two World Series championships. In 1985, he was elected to the Baseball Hall of Fame.

Born on June 18, 1939, in El Dorado, Ark., Brock grew up in Collinston, La., in a family of sharecroppers who picked cotton. At the age of 9, he was inspired by possibilities beyond the poverty and segregation of the rural South.

As a boy, he never played organized baseball. However, he received an academic scholarship to Southern University in Baton Rouge, La., and played baseball there.

Buck O’Neil, the longtime Negro leagues player and manager who was scouting for the Cubs, saw Brock. The Cubs’ signed Brock in August 1960, making his major league debut in the ’61 season.

In 1964, the Cardinals traded Brock, hoping that his speed would provide the missing element.

Playing in more than 100 games for the ’64 Cardinals, Brock hit .348, stole 33 bases, and scored 81 runs.

For Brock, base stealing required a certain bravado. He once said, “You know before you steal a base that you’ve got nine guys out there in different uniforms. You’re alone in a sea of enemies.”

“The only way you can hold your own is by arrogance, the ability to stand before the crowd. Every time you get thrown out, you’ve got to believe that somebody owes you four or five steals,” he added.

Brock retired after the 1979 season, with a career batting average of .293 to complement his base-stealing superlatives.

His survivors include his third wife Jacqueline, whom he married in 1996, son Lou Jr., and daughter Wanda from his first marriage to Katie Hay, three stepchildren, and two granddaughters, according to St. Louis Public Radio. Brock’s first two marriages ended in divorce.