1984 : X Windows, early graphics system for Unix, created by MIT
1985 : GNU Manifesto founded by Richard Stallman. Include freedom to run, to study, to redistribute, to modify and to improve. Include a set of compilers, userspace tools, editors, etc.
1991
GNU General Public License v2.0 : "The licenses for most software are designed to take away your freedom to share and change it. By contrast, the GNU General Public License is intended to guarantee your freedom to share and change free software"
Linux, Python
1993 : Debian
1994 : Red Hat
1995
Apache, Mysql
GIMP (GNU Image Manipulation Program). Inspired by Photoshop, started at Berkeley. Led to GTK+ being created. Initial cultural pool for GNOME hackers.
Windows 95
1996
PostgreSQL
KDE : First major effort at a coordinated Desktop Project. Based on Qt as widget toolkit, but this was not free software.
1997
Miguel announces GNOME project. GNOME vs KDE desktop war.
Massive fight breaks out across the Linux scene. C vs C++; Germany vs America; Corporate vs Hackers; Qt vs GTK+
1998
Mozilla
Windows 95 rocketed to take 98% PC market share
2001
Dotcom bubble burst
OSX 10.0 released
2004
Ubuntu : Combined Debian, GNOME and the kernel into a useful and usable product. Focus on users. Drove GNOME 2.x to a dominant position across the Linux ecosystem.
2017
Ubuntu returns to using GNOME by default.
References
Jonathan Blandford (July 29, 2017) "A Brief History of GNOME" Manchester : The GNOME Conference GUADEC