Billionaire Paul Allen, who founded US software giant Microsoft with Bill Gates in the 1970s, died on Monday at the age of 65 after his latest battle with cancer, his family said. Allen said earlier this month he was being treated for non-Hodgkin's lymphoma, the same kind of cancer he battled and overcame nearly a decade ago. He was first diagnosed when he was CEO of Microsoft. Allen was the man who persuaded school-friend Bill Gates to drop out of Harvard to start what became the world's biggest software company. Allen left Microsoft in 1983 - before the company became a corporate juggernaut - following a dispute with Gates, but 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.