The church fathers made a significant contribution to the almost complete preservation of the Placita of Aëtius. In this chapter I investigate what motivated them to use it so extensively. I first introduce the Placita, outlining six features that give this work a distinctive mode of ordering knowledge. Philo of Alexandria, the first of eight authors to be discussed, is not a Christian. Nevertheless his approach to the variety of philosophical doctrines recorded in the antecdent tradition of the Placita will be crucial for his Christian successors. These commence with Athenagoras and Hermias, followed by three fourth-century authors, Eusebius, Pseudo-Justin and Nemesius, and conclude with two fifth-century writers, Cyril of Alexandrian and Theodoret. Although the Placita bring order into the vast body of contradictory doctrines put forward by the philosophers, this ‘structured disorder’ is in sharp contrast to the ordering of Christian knowledge, which is presented as being founded on a unified body of revealed truth.