Emacs is much, much older than Linux. The original Emacs was written in 1976. Gosling Emacs, the first Emacs to run on Unix, was written in 1981. Gnu Emacs was written by Stallman in 1984.[1]
Linux was first released many years later, in 1991.[2]
[1] https://en.wikipedia.org/wiki/Emacs
[2] https://en.wikipedia.org/wiki/Linux