Paul G. Allen, who co-founded Microsoft with his childhood friend Bill Gates before becoming a billionaire philanthropist who invested in conservation, space travel, arts and culture and professional sports, died Monday. He was 65.
He died in Seattle from complications of non-Hodgkin's lymphoma, his company Vulcan Inc. announced.
Gates said he was heartbroken about the loss of one of his "oldest and dearest friends."
"Personal computing would not have existed without him," Gates said in a statement.
"But Paul wasn't content with starting one company. He channeled his intellect and compassion into a second act focused on improving people's lives and strengthening communities in Seattle and around the world. He was fond of saying, 'If it has the potential to do good, then we should do it,'" Gates wrote.