I did not mean to imply it was a Lisp. It was designed to solve the same problems as lisp, i.e. symbolic manipulation; and was used to rewrite code originally written in Lisp.
ML was at first a domain specific language for writing/assisting proofs: a) maths-like notation, b) functional, c) statically typed, ...
Lisp did only do b) to some extent. It was and still is common to develop languages as internal or external domain specific languages on top of Lisp. ML was such an example. Often these languages then are/were ported away from Lisp to a specialized (and possibly smaller/more efficient) implementation. Thus Lisp served as a prototyping environment.
