One of the NBA's all-time greats is now gone, as Boston Celtics legend, 11-time NBA champion, and Olympic Gold medalist William Felton Russell, best known as Bill Russel, passed away on Sunday. He was 88 years old.

His official Twitter page released a statement, saying that memorial arrangements for the "Most Prolific Winner in American Sports History" will be announced soon.

With 11 rings, he had more than Kobe Bryant and Stephen Curry combined. Yahoo! Sports also reported that he was 28-2 in elimination games, and this was at the professional, collegiate, and Olympic levels. 

He rarely lost a playoff series and should be in the "Greatest of All Time" conversations with Michael Jordan, Kobe Bryant, and Lebron James. 

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Bill Russell's Stellar Career Extended Out of the Basketball Court

The 5-time NBA Most Valuable Player (MVP) wasn't just a winner but also a humanitarian. He was part of the civil rights movement alongside Martin Luther King Jr. 

When his close personal friend King was assassinated in Memphis, Bill Russell rallied his Celtics to move past a 3-1 deficit against the Philadelphia 76ers and move on to win the NBA Finals against the Celtics' eternal rivals, the Los Angeles Lakers. 

He had an intense rivalry with the great Wilt Chamberlain. Individually, Wilt was a better player. However, the Celtics were a team and overcame Chamberlain's teams through teamwork and intense defense. 

He also had many Hall of Fame teammates throughout his career. According to Bleacher Report, these include the "Houdini of the Hardwood" himself, Bob Cousy, John Havlicek, Tom Heinsohn, K.C. Jones, Sam Jones, Bill Sharman, Clyde Lovellette, Frank Ramsey, Tom Sanders, Arnie Risen, Bailey Howell, and Andy Phillip. 

He was also coached by one of the greatest coaches of all time, Red Auerbach, who led the Celtics dynasty. He was also the first black coach in NBA history and the first black coach in any North American sport. 

Russell was a true trailblazer in that aspect, serving as player-coach for the Boston Celtics, and then went on to coach the Seattle Supersonics (1973-77) and the Sacramento Kings (1987-88) after retirement from being a player.

He managed to reach the playoffs with Seattle, but he never had the same success as he had in Boston. After retirement, he was so revered by those who came after him that he would often play peacemaker among feuding players.

That includes telling Shaquille O'Neal to approach and talk to Kobe Bryant during a game between O'Neal's Miami Heat and Bryant's Los Angeles Lakers in 2006.

This was when the relationship between both NBA superstars turned frosty following O'Neal's departure from the Lakers. CBS Sports reported that O'Neal actually greeted Bryant and said, "I had orders from the great Bill Russell."

Barack Obama, the NBA World Reacts to Bill Russell's Death

Then-President Barack Obama awarded Bill Russell for his many achievements as a player and coach. He also made a huge impact as a civil rights activist. Obama reacted to Russell's death on Twitter:

Another NBA legend, Michael Jordan, released a statement via the Charlotte Hornets Twitter page:

The Boston Celtics and the NBA organization also paid a touching tribute to the legendary center.

Other NBA players, both past and present, also released their condolences to Russell's bereaved family:

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This article is owned by Latin Post.

Written by: Rick Martin

WATCH: Bill Russell, NBA Legend and Hall of Famer, Dies at 88 - From ABC News