Paul Allen, who founded Microsoft with Bill Gates in the 1970s and later went on to become an investor, philanthropist and sports owner, died yesterday after his latest battle with cancer at age 65.
Mr Allen died just two weeks after publicly revealing that non-Hodgkin's lymphoma he fought into remission nine years ago had returned. The incurable cancer affects white blood cells.
"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," his sister Jody said in a statement announcing his death.
He was a high school classmate of Bill Gates in Seattle, and later, while working as a computer programmer, persuaded his friend to drop out of Harvard to create Microsoft, which became the world's most valuable company in the 1990s.
In recent years, Mr Allen was known as the owner of the NFL's Seattle Seahawks and the NBA's Portland Trail Blazers, and part owner of the Major League Soccer team the Seattle Sounders, along with a variety of business and charitable ventures.
One of the world's wealthiest billionaires, Mr Allen also founded Stratolaunch Systems, which built the world's largest plane designed as a colossal rocket-launching aircraft touted as the future of space travel.
The craft was on track for its first launch demonstration as early at 2019.
A music-lover, he had a list of high-profile friends in the entertainment business, including U2 singer Bono, but preferred to avoid the limelight at his compound on Mercer Island, across Lake Washington from Seattle, where he grew up.
In the world of sports, Mr Allen in 1988 bought the Trail Blazers, taking the team to the NBA finals twice.
He was also credited with putting Seattle on the map for the NFL.
"Paul Allen was the driving force behind keeping the NFL in the Pacific Northwest," NFL Commissioner Roger Goodell said in a statement.
"His vision led to the construction of CenturyLink Field and the building of a team that played in three Super Bowls, winning the championship in Super Bowl XLVIII. "
His personal charitable foundation gave to a diverse array of causes including anti-poaching initiatives in Africa, climate and energy research, and projects on homelessness, as well as the arts and culture.
In his 2011 memoir "Idea Man," he described a somewhat stormy relationship with Mr Gates in the early days of Microsoft.
Mr Allen wrote that he had expected a 50-50 split in the new company, but Mr Gates insisted on taking 60%, and later raised it to 64%, claiming that Mr Gates schemed to "rip me off".
He never married and had no children.
