The powerful LOOP macro was invented in the early seventies in Interlisp at Xerox PARC. It was called FOR there. It was then reimplemented in Maclisp and Lisp

The powerful LOOP macro was invented in the early seventies in Interlisp at Xerox PARC. It was called FOR there. It was then reimplemented in Maclisp and Lisp Machine Lisp in the late 70s as the LOOP macro we know now. It was then ported to Common Lisp and later added to the standard, after looking at several alternatives.