Paul Allen, the co-founder of Microsoft, owner of the Seattle Seahawks, and major Seattle real estate developer, died Oct. 15 due to complications with his cancer.

“It is with deep sadness that we announce the death of our founder Paul G. Allen, co-founder of Microsoft and noted technologist, philanthropist, community builder, conservationist, musician and supporter of the arts. Mr. Allen died on Monday afternoon, October 15, 2018, from complications of non-Hodgkin’s lymphoma in Seattle,” according to a joint statement from the Allen family, his multi-faceted investment firm Vulcan, and the Paul G. Allen Network.

Allen was first diagnosed with non-Hodgkin’s lymphoma back in 2009, but struggled with cancer going back to the 1980s. As recently as two weeks ago, Allen announced that he was undergoing treatment and planned on fighting the condition “aggressively.”

Alongside his high school friend Bill Gates, Allen co-founded Microsoft in 1975, but eventually left in 1981 because of a Hodgkin’s disease diagnosis. He went on to pursue philanthropy, sports team ownership — he owned both the Seahawks and the Portland Trail Blazers, as well as a stake in the Seattle Sounders — and real estate development through his company, Vulcan Inc.

Notable projects include remaking South Lake Union into the city’s tech hub, along with the Yesler Terrace redevelopment project. As of Oct. 15, Forbes estimated Allen was worth $20 billion and that he gave away close to $2 billion in philanthropy — such as funding the Experience Music Project rock ‘n’ roll museum at Seattle Center, Upstream Music Festival, and founding the Allen Institute for Brain Science.

Vulcan CEO Bill Hilf said in a press release that the company will “continue to work on furthering Paul’s mission and the projects he entrusted to us. There are no changes imminent for Vulcan, the teams, the research institutes or museums.”

Allen occasionally garnered criticism from left-leaning actors for some of his political activity, such as giving $100,000 to help defeat a ballot initiative that would have enacted a statewide income tax and, more recently, by giving $100,000 to help Republicans retain control of the U.S. House of Representatives during the 2018 midterm elections.

“My brother was a remarkable individual on every level. While most knew Paul Allen as a technologist and philanthropist, for us he was a much loved brother and uncle, and an exceptional friend,” Allen’s sister, Jody Allen, said in the release. “Paul’s family and friends were blessed to experience his wit, warmth, his generosity and deep concern. For all the demands on his schedule, there was always time for family and friends. At this time of loss and grief for us — and so many others — we are profoundly grateful for the care and concern he demonstrated every day.”