Paul Allen, who co-founded Microsoft with Bill Gates in 1975, has died as a result of complications from non-Hodgkin's lymphoma. He was 65.

"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 a statement.

"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."

Microsoft released a statement in the wake of his passing, calling Allen's contributions to the company, industry, and community "indispensable." Apple CEO Tim Cook paid tribute to Allen as a "pioneer" and "force for good," while Google CEO Sundar Pichai expressed thanks to Allen for his "immense contributions to the world through your work and your philanthropy."

Statement from Microsoft CEO Satya Nadella on the passing of Paul Allen: pic.twitter.com/1iLDLenLKzOctober 15, 2018

Allen left Microsoft in 1983 following a diagnosis for Hodgkin's lymphoma, although he remained on the board of directors until 2000. Despite leaving the company during its relatively early days, he was extraordinarily wealthy, with an estimated net worth in excess of $20 billion. He founded the privately held company Vulcan in 1986 to oversee his business and philanthropic efforts; he was also the owner of the NBA's Portland Trail Blazers and the Seattle Seahawks football team, both of which paid tribute to Allen on social media.