Many early lisps had dynamic scoping only. It meant that this code would return 5

  (defvar x 1)    ; new global var 

  (defun foo () x)  ; function returns x

  (+ (let ((x 4)) (foo)) (foo)) ; => 5

It also meant that anonymous functions weren’t closures. Later on, scheme used lexical scoping and Common Lisp used lexical scoping normally with dynamic scoping for special (typically global) variables like standard-input. At the time, implementers were worried that they wouldn’t be able to do lexical scoping efficiently.

Emacs lisp only had dynamic scoping for a long time. Furthermore it had buffer-local-variables where the editor has a notion of the current buffer, buffers can have definitions of variables, and the value you get for a variable depends on what it is bound to within that buffer as well as dynamically. Over time elisp got true closures/lexical scope, first via a library and later as a language feature (if a certain buffer-local variable is set when you compile/evaluate a file, you get lexical scoping; the easy way to set it is by writing a specially formatted line in the file which allows emacs to set ‘safe’ buffer local variables on opening the file.