On February 13, 1991, Borland released Pascal for Windows, bringing the hugely popular teaching language into the GUI era and introducing a generation of programmers to event-driven development — a stepping stone that led directly to Delphi, one of the most productive Windows IDEs of the 1990s.
On February 20, 1991, Guido van Rossum released Python 0.9.0 on Usenet — a small, readable language built over the Christmas holidays that prioritized human clarity over machine efficiency, and grew into one of the most widely used programming languages in the world.
In April 1991, AT&T sued BSD, claiming its Unix System V code had been used without permission. The three-year legal battle froze BSD development at a critical moment — and inadvertently handed Linux the window it needed to dominate.
