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.