Marvelous Marvin Hagler, the boxing legend who was the undisputed middleweight champion from 1980 to 1987 and recorded 52 knockouts during his career, passed away yesterday at 66.

His wife, Kay G. Hagler, made the announcement:

“I am sorry to make a very sad announcement. Unfortunately my beloved husband Marvelous Marvin passed away unexpectedly at his home here in New Hampshire. Our family requests that you respect our privacy during this difficult time. With love.”

His cause of death was not immediately known.

Hagler is known for being one of the greatest middleweight fighters of all time. He finished his boxing career with a 62-3-2 record. He was known for his ring wars with Roberto Duran, Thomas Hearns and Sugar Ray Leonard during his career.

The last fight of his career was against Leonard in 1987 at Caesars Palace in Las Vegas. Leonard beat him via split decision and took Hagler’s WBC and The Ring middleweight titles. The split decision victory for Leonard is one of the most-debated decisions in the sport’s history. Several writers from various publications scored the fight in favor of Hagler despite the boxing judges’ own scorecards.

The New Jersey southpaw is an International Boxing Hall of Famer and World Boxing Hall of Famer. Ring Magazine had previously ranked him as the fourth-best middleweight of all-time.