How, then, is a living being conceived? Is the substance of both body and soul formed together at one and the same time? Or does one of them precede the other in natural formation? We indeed maintain that both are conceived, and formed, and perfectly simultaneously, as well as born together; and that not a moment’s interval occurs in their conception, so that, a prior place can be assigned to either.
Tertullian
A Treatise on the Soul
Chapter XXVII