alterius non sit qui suus esse potest
Let no man be another's who can be his own
Notes
Final sentence from Aesop ascribed fable (see also Aesop's Fables) "The Frogs Who Desired a King" as appears in the collection commonly known as the "Anonymus Neveleti" (fable XXIb. De ranis a Iove querentibus regem). Motto of Paracelsus. Usually attributed to Cicero.