Paul Allen, who co-founded Microsoft with Bill Gates and chaired Vulcan Inc., died Monday in Seattle from complications of non-Hodgkin’s lymphoma. He was 65.

Allen was born in Washington State in 1953 where he attended both high school and college, before dropping out of Washington State University in the 1970s to co-found Microsoft with his high school friend Gates. However, Allen would leave the company in 1983 due to a battle with Hodgkin’s disease, which he eventually won.

“I am heartbroken by the passing of one of my oldest and dearest friends, Paul Allen,” Bill Gates said in a statement. “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.”

Allen — who had a net worth of $26.1 billion at the time of his death, according to Bloomberg data — had interests ranging far beyond PCs. In 1997, Allen co-founded Vulcan Productions with his sister, Jody. Vulcan was involved in films including “Far From Heaven,” “Hard Candy,” “Racing Extinction,” “Girl Rising” and most recently, an adaptation of Naoki Higashida’s bestseller “The Reason I Jump,” a documentary about autism.

Allen’s creativity also transferred to the music industry where he released an album with his band the Underthinkers in 2013. Their debut blues-rock album, “Everywhere at Once,” features Allen’s electric guitar on several songs including “Straw Into Gold,” “Six Strings From Hell” and “Pictures of a Dream.” He also takes the guitar solos on “Down Low” and “Big Blue Raindrops.”

Among his business ventures, Allen aspired to become a major cable-operator player. After he acquired Charter Communications in 1998 for $4.5 billion, the operator amassed subscribers through a series of acquisitions over the next decade — before a massive debt load forced it into bankruptcy in 2009 and Allen relinquished control.

Other Allen interests included professional sports teams, aviation and brain research. Allen owned the Seattle Seahawks and the Portland Trail Blazers as well as a minority stake in the Seattle Sounders FC soccer team. Allen also funded SpaceShipOne, the first private aircraft to successfully put a civilian in suborbital space, and invested millions of dollars into the Allen Institute for Brain Science.

He also owned Portland’s Moda Center, Seattle’s Cinerama Theater and London’s Hospital Club, which is planning a Los Angeles branch.

Allen’s philanthropic work was similarly diverse. The business mogul founded Seattle’s Museum of Pop Culture, previously called the Experience Music Project, and donated more than $1.5 billion to various organizations after becoming one of the first billionaires to join Gates and Warren Buffett’s Giving Pledge in 2010.

Jody Allen said in a statement on behalf of the Allen family that he 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 Allen said. “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 issued a statement from CEO Satya Nadella, who said, “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.”

Statement from Microsoft CEO Satya Nadella on the passing of Paul Allen: pic.twitter.com/1iLDLenLKz — Microsoft (@Microsoft) October 15, 2018

Allen was diagnosed with non-Hodgkin’s lymphoma in 2009 and on Oct. 1, 2018, tweeted that it had returned.

Some personal news: Recently, I learned the non-Hodgkin’s lymphoma I battled in 2009 has returned. I’ve begun treatment & my doctors are optimistic that I will see a good result. Appreciate the support I’ve received & count on it as I fight this challenge. https://t.co/ZolxS8lni5 — Paul Allen (@PaulGAllen) October 1, 2018

Former Microsoft CEO Steve Ballmer tweeted, “Paul was a truly wonderful, bright and inspiring person — and a great friend. I will miss him.”

Paul was a truly wonderful, bright and inspiring person—- and a great friend. I will miss him https://t.co/HYhtgZGo8C — Steve Ballmer (@Steven_Ballmer) October 15, 2018

Apple CEO Tim Cook extended condolences to the Allen family and “everyone at Microsoft” — which historically was a major Apple rival — saying in a tweet, “Our industry has lost a pioneer and our world has lost a force for good.”

Jeff Bezos, founder and CEO of Amazon, also tweeted about Allen, saying of the fellow Seattleite, “His passion for invention and pushing forward inspired so many. He was relentless to the end. My heart goes out to Paul’s family and friends.”