It was 40 years ago, on April 1, 1976, that three men signed a contract that would go down in history.

“WHEREAS,” it read, “Mr. Stephen G. Wozniak (hereinafter referred to as WOZNIAK), Mr. Steven P. Jobs (hereinafter referred to as JOBS), and Mr. Ronald G. Wayne (hereinafter referred to as WAYNE), all residents of the County of Santa Clara, State of California, have mutually agreed to the formation of a company to be specifically organized for the manufacture and marketing of computer devices, components, and related material, said company to be organized under the fictitious name of APPLE COMPUTER COMPANY.”

On April 12, however, an amendment was filed. Ronald Wayne was giving up his status as partner, and all of his obligations and responsibilities would be taken over by Jobs and Wozniak. In exchange, he would receive $800. (He later received another $1,500 from the company.)

Wayne, as he would later explain in his memoir Adventures of an Apple Founder, had first gotten involved when Jobs and Wozniak had a “modest philosophical difference” and Jobs, who had met Wayne through his work at Atari, asked for advice.

Read more: Behold, Some of the First Apple Computer Photos Ever

That decision has made Wayne famous for giving up a stake in the company that would be worth billions of dollars today. In 2010, he told the San Jose Mercury News that he walked away partly out of fear that his much-younger co-founders couldn’t hack the business side, and that he was “terrified to be the only one of the three founders with assets that creditors could seize.” In 2012, on Facebook, Wayne offered a full explanation, from his perspective, of why he walked away:

I didn’t separate myself from Apple because of any lack of enthusiasm for the concept of computer products. Aside from any immediate apprehension in regard to financial risks, I left because I didn’t feel that this new enterprise would be the working environment that I saw for myself, essentially for the rest of my days. I had every belief would be successful but I didn’t know when, what I’d have to give up or sacrifice to get there, or how long it would take to achieve that success… If I had known it would make 300 people millionaires in only four years, I would have stayed those four years. And then I still would have walked away. Steve and Steve had their project. They wanted to change the world in their way. I wanted to change the world in my own.

In 2011, one of the original contracts was sold at auction for $1.35 million. It was Ronald Wayne’s copy.

Get our History Newsletter. Put today's news in context and see highlights from the archives. Please enter a valid email address. Sign Up Now Check the box if you do not wish to receive promotional offers via email from TIME. You can unsubscribe at any time. By signing up you are agreeing to our Terms of Use and Privacy Policy . This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply. Thank you! For your security, we've sent a confirmation email to the address you entered. Click the link to confirm your subscription and begin receiving our newsletters. If you don't get the confirmation within 10 minutes, please check your spam folder.

Write to Lily Rothman at lily.rothman@time.com.