Last updated at 2:29 pm UTC on 4 October 2019
The first machines were introduced on 1 March 1973.
The Xerox Alto was the first computer designed from its inception to support an operating system based on a graphical user interface (GUI), later using the desktop metaphor.
In December 1979, Apple Computer's co-founder Steve Jobs visited Xerox PARC, where he was shown the Smalltalk-80 object-oriented programming environment, networking, and most importantly the WYSIWYG, mouse-driven graphical user interface provided by the Alto
5 years later the personal computer Apple Macintosh was introduced (Jan 1984).