Although Microsoft Word developed for use with MS-DOS and later for the Apple Macintosh and Microsoft Windows had been around since 1983, the first official version of the group of desktop applications (Excel, Powerpoint, Word) known as Microsoft Office was released in 1989 for the Mac. Despite a seemingly good working relationship between the two companies, just a year before, Apple had filed a suit against Microsoft claiming that its Windows interface was illegally similar to Apple's OS. The six-year court battle netted Apple a loss and effectively cemented Microsoft's reign as the world's leading computer software manufacturer.