Also, there were other emacses that preceded GNU Emacs and were written from scratch: Bernard Greenberg's MULTICS Emacs, written in MacLisp [1], James Gosling's Unix Emacs, mostly written in C [2], and Daniel Weinreb's Zwei, written in Lisp Machine Lisp [3].

1.https://multicians.org/mepap.html

2.https://dl.acm.org/doi/10.1145/62402.62417

3.https://en.wikipedia.org/wiki/EINE_and_ZWEI