Apple was created in the 1970s. It was first implemented on the Apple I computer, released in July 1976. Windows was not developed until 1982, but its predecessor MS-DOS was created in 1980. They were both startups founded by groups of college classmates. Apple employee John Sculley left for Microsoft in 1985, bringing with him insights that allowed them to include similar functionality in Apple programming. This made Windows one of Apple's biggest competitors. In 1997 an alliance was created between the two, Microsoft invested 150 million dollars in Apple shares and Apple included Internet Explorer in its Mac operating system