Paul G. Allen, the co-founder of Microsoft, died in the afternoon of Monday, October 15, 2018, at the age of 65. The cause of death was complications associated with non-Hodgkin’s lymphoma. The disease returned recently after Allen was in remission for many years following his first brush with cancer in the early 1980’s. He left Microsoft shortly after learning that he had cancer.

Allen was a force to be reckoned with during the first seven years of Microsoft’s existence, and it was actually Allen who came up with the name Micro-Soft, a play on the fact that the company made software for small computers. When Microsoft promised to deliver the operating system for IBM’s entry into the personal computer business, Allen was instrumental in putting together a deal that would allow Microsoft to buy an early operating system from a Seattle programmer to use as a base for what would later become the most widely used operating system in the world. The system was introduced in 1981 as Microsoft Disk Operating System, or MS-DOS, and would later be transformed into the Windows operating system.

Bill Gates, who co-founded Microsoft with Allen, began working with Allen when they were teenagers and continued to do so into their adult lives. Gates said, “From our early days together at Lakeside School, through our partnership in the creation of Microsoft, to some of our joint philanthropic projects over the years, Paul was a true partner and dear friend. Personal computing would not have existed without him.”

After leaving Microsoft, Allen focused on philanthropy work in Seattle. He restored the old Cinerama movie theater and bought both the Portland Trail Blazers and Seattle Seahawks in order to keep the teams in his home city of Seattle. Bill Hilf said on behalf of the Seahawks and Trailblazers, “Paul loved Seattle and the Pacific Northwest. The impact of Paul’s efforts can be seen here at every turn. But the true impact of his vision and generosity is evident around the globe.”

Allen is survived by his sister, Jody Allen. He is remembered for his extraordinary accomplishments and for “[the] wit, warmth, [the] generosity and deep concern” he displayed around his family and friends. There is no doubt the world has lost a giant.