Steve Jobs resigned from Apple, a company he had co-founded nine years back, on 17th September 1985. He had been involved with bitter in-fighting with, the then CEO, John Sculley. In fact, a few years before, Jobs had himself asked Sculley to leave his position in Pepsico and join Apple.
Steve Jobs went on to set up NeXT Computers on whose machines the World Wide Web was invented by Sir Tim Berners-Lee at CERN. NeXT was later acquired by Apple when Steve Jobs rejoined his old company.