George Foreman, a two-time heavyweight champion, died at the age of 76

"Big" George Foreman, one of boxing's most important and famous figures, died Friday, according to his family's social media account. He was 76.

"A devout preacher, a devoted husband, a loving father, and a proud grand and great grandfather, he lived a life marked by unwavering faith, humility, and purpose," the statement said. "A humanitarian, an Olympian, and two-time heavyweight champion of the world, He was deeply respected — a force for good, a man of discipline, conviction, and a protector of his legacy, fighting tirelessly to preserve his good name— for his family."

His family supplied no information on the cause of death.

In the ring, the American was known as Big George, and he fashioned one of the most spectacular and enduring careers in the sport, earning Olympic gold in 1968 and taking the world heavyweight title twice, 21 years apart, the second making him the oldest champion in history at 45.

At the age of 24, Foreman won his first heavyweight belt with a shocking knockout of undefeated world champion Joe Frazier in 1973.

He is arguably most remembered for his famous Rumble in the Jungle battle with Muhammad Ali in 1974 in Zaire, which Foreman lost in an upset via eighth-round knockout. It's possibly the most famous fight of all time, and the documentary film "When We Were Kings" about it earned an Academy Award for best documentary feature.

Foreman, of course, made history once again later in his career. After losing the heavyweight championship to Ali at the age of 25, he fought five more times, including a fifth-round TKO victory over Joe Frazier (who he had previously finished in two rounds to win the title) and a fifth-round KO of Ron Lyle in a legendary slugfest.

After his sixth bout at the age of 28, Foreman unexpectedly declared his retirement and began working as an ordained priest in his home state of Texas.

When Foreman returned to the ring after a 10-year absence, many questioned whether a boxer his age could beat any younger competitor, let alone return to the top of the game. However, in 1994, he shocked the boxing world by defeating the undefeated Michael Moorer and reclaiming the world championship.

Foreman's career spanned generations, as he faced Chuck Wepner in the 1960s, Joe Frazier and Muhammad Ali in the 1970s, Dwight Muhammad Qawi in the 1980s, and Evander Holyfield in the 1990s.

And his fame allowed him to make millions of dollars selling grills after retirement. He became an ad pitchman for his George Foreman Grill, which has sold millions since its introduction in 1994, owing in part to his popular slogan, the "Lean Mean Grilling Machine".

In 1999, he sold the commercial rights for the George Foreman grill for $138 million.

Foreman's final bout was against Shannon Briggs in November 1997, and he lost by majority decision.

He worked as a ringside analyst for HBO for 12 years until leaving in 2004.

In 2002, The Ring ranked Foreman one of the 25 finest boxers of the last 80 years and the ninth-greatest puncher of all time.

George Edward Foreman was born on January 10, 1949, in Marshall, Texas, to Nancy Ree (Nelson) and J.D. Foreman. Foreman was the sixth of seven children and grew up "in the toughest neighborhood in Houston," according to his book "George Foreman's Guide To Life: How to Get Up Off the Canvas When Life Knocks You Down," released in 2003. "I did not have much to look forward to in life. At least, I didn't believe I did. I was often hungry, dropped out of school in eighth grade, and depended on my size and fists to get by."

Foreman got married five times. He has 12 children. Five of his sons share the name George.

He claimed on his website that he named them after himself so that "they would always have something in common".

"I say to them, 'If one of us goes up, then we all go up together," he explained. "And if one goes down, we all go down together!'"