Abstract
In this paper I argue that Leibniz' (L.) concept of entelechy, though L. himself believes to have derived it directly from Aristotle, does not correspond exactly to the Aristotelian concept. The main difference between the Aristotelian and the Leibnizian concept may be explained as follows: Whereas Aristotle uses "entelecheia" to designate a property possessed by living organisms, L. takes it to be a generic term for souls and other monads. It is further argued that Aristotle's somewhat intricate argument in De Anima II 1 has contributed to the misunderstanding of the Aristotelian term, a misunderstanding starting already with the Aristotelian commentators Themistius, Philoponus and Simplicius. L. took his concept from the tradition of the commentators which he knew through the Italian humanist Ermolao Barbaro.