Pittsburgh Steelers chairman Dan Rooney died Thursday at the age of 84 after a brief illness, the team announced.

On Tuesday morning, his funeral mass will be held at St. Paul Cathedral in Oakland, where he reportedly prayed. People can make memorial donations to Duquesne University and United Way of Southwest Pennsylvania.

“It is a sad day for my family and me. My father meant so much to all of us, and so much to so many past and present members of the Steelers organization. He gave his heart and soul to the Steelers, the National Football League, and the City of Pittsburgh,” Art Rooney II, Rooney’s son, said, after his father’s death. “We will celebrate his life and the many ways he left us in a better place.”

Rooney took over the Steelers operation in the 1960s from his father Art Rooney who founded the team in the early 1930s. Rooney is also credited for developing the Rooney Rule which requires NFL teams to interview at least one minority candidate for coaching and front-office vacancies. Rooney had the ability to reach across class, race, gender and status, which made him a popular figure.

"My job is to do what's best for the organization and to make that decision regardless of what the consequences are to me personally," he once said, according to the Associated Press. "I take my position very seriously. What I want is an organization that can be together, one where everybody in the place has the same goal, and that is to win."

Rooney also served as the team’s controlling owner from 1988 to 2003 before passing on the control to his son. Following this, he also served as the U.S. envoy to Ireland from 2009 to 2012.

Former President Barack Obama expressed condolences in over Rooney’s death.

“Dan Rooney was a great friend of mine, but more importantly, he was a great friend to the people of Pittsburgh, a model citizen, and someone who represented the United States with dignity and grace on the world stage,” Obama said in a statement. “I knew he’d do a wonderful job when I named him as our United States Ambassador to Ireland, but naturally, he surpassed my high expectations, and I know the people of Ireland think fondly of him today.”

“And I know the people of Pittsburgh, who loved him not only for the Super Bowl championships he brought as the owner of the Steelers, but for his generosity of spirit, mourn his passing today. Michelle and I offer our condolences to the Rooney family, some of the most gracious and thoughtful people we know – even as we celebrate the life of Dan Rooney: a championship-caliber good man.”

Condolences poured in on Twitter following Rooney’s death.