Allen had revealed earlier this month that he had begun undergoing treatment for the blood cancer, which he previously overcame nine years ago.
Born in Seattle, Wash., Allen met Bill Gates in the computer room of their high school in Seattle in 1968.
He went on to drop out of university in 1974, eventually persuading Gates to do the same. In 1975, the pair formed Micro-Soft — Allen is credited with coming up with the name, although the hyphen was later dropped.
Allen led Microsoft’s technical operations in its early years, and was involved in creating such revolutionary software programs as MS-DOS and Word.
He also predicted the ubiquity of personal computers as far back as 1977, writing in Personal Computing magazine, “I expect the personal computer to become the kind of thing that people carry with them, a companion that takes notes, does accounting, gives reminders, handles a thousand personal tasks.”
However, he is said to have lacked the commercial instincts of Gates, who is widely credited with powering Microsoft’s rise in the 1990s.
Allen left Microsoft in 1983 following a dispute with Gates. However, his share of their original partnership allowed him to spend the rest of his life and billions of dollars on yachts, art, rock music, sports teams, brain research and real estate.
He went on to set up numerous scientific research institutes including the Allen Institute of Brain Science, the Institute for Cell Science and the Institute for Artificial Intelligence; he also owned or co-owned several professional sports teams, including the NBA’s Portland Trail Blazers, NFL’s Seattle Seahawks and Seattle Sounders FC of Major League Soccer.
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Vulcan Inc. said Allen possessed “a remarkable intellect and a passion to solve some of the world’s most difficult problems,” and hailed his conviction in creative thinking to have an impact on society.
“Paul’s life was diverse and lived with gusto. It reflected his myriad interests in technology, music and the arts, biosciences and artificial intelligence, conservation and in the power of shared experience – in a stadium or a neighborhood – to transform individual lives and whole communities,” the company said.
The company also released a statement on behalf of Allen’s sister Jody.
“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,” Jody said in her statement.
“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.”
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Microsoft CEO Satya Nadella hailed Allen’s contributions to the software giant.
“As co-founder of Microsoft, in his own quiet and persistent way, he created magical products, experiences and institutions, and in doing so, he changed the world,” Nadella said.
— With files from Reuters