Plotinos: Complete Works, v. 2 In Chronological Order,...

9. Let us now examine how it happens that the soul descends into the body, and in what manner this occurs; for it is sufficiently astonishing and remarkable. For a soul, there are two kinds of entrance into a body. The first occurs when the soul, already dwelling in a body, undergoes a transmigration; that is, passes from an aerial or igneous body into a terrestrial body. This is not usually called a transmigration, because the condition from which the soul comes is not visible. The other kind occurs when the soul passes from an incorporeal condition into any kind of a body, and thus for the first time enters into relations with a body.116