Tommy Heinsohn, Boston Celtics legend and basketball Hall of Famer, passed away at the age of 86, the team confirmed Tuesday. The cause of death was unknown.

He was associated with the Boston Celtics of the NBA for nearly six decades as a player, coach, and broadcaster. He played for the Celtics from 1956 to 1965 and coached the team from 1969 to 1978.

Heinsohn won NBA Rookie of the Year for the 1956-1957 season, helping his team to enter the finals.

Celtics said he was selected to six All-Star teams and won eight championships as a player with the team, finishing his career with 12,194 points and 5,749 rebounds.

In a statement, Celtics’ owner said, “This is a devastating loss. Tommy was the ultimate Celtic. For the past 18 years, our ownership group has relied hugely on Tommy’s advice and insights and have reveled in his hundreds of stories about Red Auerbach, Bill Russell, and how the Celtics became a dynasty. He will be remembered forever.”

Russell tweeted, “We were rookies together and friends for life. In life there are a limited number of true friends, today I lost one. RIP Heiny.”

NBA Commissioner Adam Silver said, “Celtics games will not be the same without Tommy, and he will be dearly missed by those who share his fervor for basketball. We extend our deepest sympathies to Tommy’s family, his friends, and the Celtics organization.”

Heinsohn became a broadcaster for Celtics in 1981, teaming up with Mike Gorman to form a partnership that lasted several decades.

Gorman tweeted, “Roughly 2800 times I sat down with Tommy to broadcast a game. Every time it was special. HOF player…HOF coach…HOF partner. Celtics Nation has lost its finest voice. Rest In Peace my friend. It has been the privilege of my professional life to be the Mike in Mike & Tommy.”

The team said, “For all of his accomplishments as a player, coach, and broadcaster, it is Tommy’s rich personality that defined the man.”

Born on August 26, 1934, in Jersey City, New Jersey, Heinsohn also enjoyed painting and playing golf. In his later years, Heinsohn worked fewer games due to age and health issues.