BOSTON (AP) – The NBA great Bill Russell has died at age 88. His family said on social media that Russell died on Sunday.

Russell anchored a Boston Celtics dynasty that won 11 titles in 13 years. His last two were as the first Black head coach in any major U.S. sport.

Russell was a Hall of Famer, five-time MVP and 12-time All-Star. He won with defense and rebounding and waged battles with Wilt Chamberlain.

Russell also marched for civil rights with Martin Luther King Jr. and stood with boxer Muhammad Ali when he refused military induction.