Pro Football Hall of Fame tight end John Mackey, most famous for helping the former Baltimore Colts win Super Bowl V, died on July 7 from dementia, according to reports. He was 69.

BaltimoreRavens.com reports that Mackey’s wife, Sylvia first informed the Ravens organization of her husband’s death, which occurred late on July 6. He had been suffering from a decade-long battle with frontal temporal dementia. Ravens general manager Ozzie Newsome, a Hall of Fame tight end himself, claimed Mackey paved the way for players like himself to make it in the league.

“John revolutionized the tight end position during his Hall of Fame career,” Newsome told BaltimoreRavens.com, explaining how Mackey was one of the first tight ends used as a receiver down the field. “He laid the foundation on and off the field for modern NFL players.”

After serving 10 seasons in the NFL (nine with the Colts), Mackey remained active with the league, becoming the first president of the NFL Players’ Association. As president, he helped introduce the option of free agency to the NFL, while also advocating for better health benefits and pension relief for retired players.

“John Mackey is still a leader. As President of the NFLPA he led the fight for fairness with brilliance and ferocious drive,” current NFLPA Executive Director DeMaurice Smith stated via a July 7 Twitter. “John Mackey has inspired me and will continue to inspire our players and define our institution. He will be missed but never forgotten.”

Bruce Laird, President of Fourth and Goal United, the official alumni association for NFL players, said Mackey’s “diagnosis of dementia was the catalyst for the founding of Fourth and Goal,” and its 88 Plan, a health pension plan that allotted up to $88,000 yearly for nursing expenses.

“The 88 Plan, named in John’s honor (Mackey wore the jersey No. 88), provides care for those afflicted with dementia, Alzheimers and similar neurological diseases,” Laird explained in a released media statement.

“Other resources have been made available to retired players. Yet John’s struggle with dementia reminds us every day that the league, the union, the players, and the fans must be committed to player safety and to assisting those who, like John, suffer the consequences of football injuries.”

Among the many responding to the news of the Mackey passing was Maryland Governor Martin O’Malley, who stated:

“Today, we reflect on the life of John Mackey, a great Baltimore Colt and one of football’s legendary players.

“His remarkable talents on the football field revolutionized the tight end position and earned him a place in history in the Hall of Fame, while his loyalty, determination and integrity off the field have earned him a place in our hearts.

“We are saddened by his passing and our thoughts and prayers are with his family and friends at this time.”