1680s, from Middle French simplification "act or process of simplifying," from simplifier (see simplify).
1650s, from French simplifier "to make simpler" (15c.), from Medieval Latin simplificare "to simplify," from Latin simplex "simple" (see simplex) + root of facere "to make" (see factitious). Meaning "to make easier to do" is from 1759. Related: Simplified; simplifying.