Emacs' first public release was 40 years ago today, 20 March 1985

That's _GNU_ Emacs. The original Emacs is even older (1976), though back then it was still a set of TECO macros rather than a C core with Lisp macros.

Interestingly, the very first version of Emacs on the PDP-10 in 1976 was already developed by Richard Stallman.