Boston Celtics legend Bill Russell has passed away at the age of 88. The 11-time NBA Championship winner’s death was announced on social media Sunday afternoon (July 31).

A statement posted to Russell’s social media accounts revealed he “peacefully” transitioned with his wife Jeannine by his side. “Perhaps you’ll relive one or two of the golden moments he gave us, or recall his trademark laugh as he delighted in explaining the real story behind how those moments unfolded,” read the statement.

It goes on to highlight some of the prolific basketball star’s greatness. “Along the way, Bill earned a string of individual awards that stands unprecedented as it went unmentioned by him. In 2009, the award for the NBA Finals most valuable player was renamed after two-time Hall of Famer as the ‘Bill Russell NBA Finals Most Valuable Player Award.”

Some of his other career highlights include the slew of back-to-back championships he helped the Celtics win, 12 All-Star appearances and earning an Olympic gold medal in 1956. While Russell dominated the court during his 13 seasons in the league, he was also revered as a civil rights advocate.

In 2011, he was awarded the Presidential Medal of Freedom. Eight years later he was awarded the Arthur Ashe Courage Award at the ESPYs. The award recognizes athletes’ contributions that transcend sports. Los Angeles Laker legend Kobe Bryant presented him with the award.

“Every generation has a responsibility to teach the next. One thing I learned about Bill was how he drew inspiration from his grandfather, whose motto was, ‘A man has to draw a line within himself that he will not allow any man to cross,'” said Bryant in a heartfelt speech. He continued, “Bill learned from that and added his own motto: ‘You disrespect the line, you disrespect me.’ More than 50 years later, Bill and his grandfather’s mottos still resonate powerfully and still speak loudly for Bill’s beliefs.”

Arrangements for a memorial service are expected to be released soon. Check out some of the fan tributes that have begun to flood social media.