In the _Apology_ of Quadratus we should obtain a picture of the popular theology of the Church during that dark period which elapsed between the days of Clement of Rome and Ignatius, and those of Justin Martyr. The _Apology_ of Aristides which has been found reveals something indeed in the same direction, but is more occupied with an attack upon paganism than in a statement of the Christian faith. Here, however, consists its bearing on the Acts of the Apostles, not directly, but by way of contrast. Let me explain what I mean. In lecture xvii., when treating of the story of Simon Magus, I have shown how the simple narrative of the Acts concerning that man became elaborated in the second century till it formed at last a regular romance; whence I conclude that if the Acts had been written in the second century the story of Simon Magus would not be the simple matter we read in St. Luke's narrative. Now our argument for the date of the Acts derived from the _Apology_ of Aristides is of much the same kind. This document shows us what the tone and substance of second century addresses to the pagans were. It is the earliest of a series of apologies extending over the whole of that century. The _Apology_ of Aristides, the numerous writings of Justin Martyr, specially the _Oratio_ and the _Cohortatio ad Græcos_ attributed to him, the _Oration_ of Tatian addressed to the Greeks, the _Apologeticus_ and the treatise _Ad Nationes_ of Tertullian, the _Epistle to Diognetus_, the writings of Athenagoras, all deal with the same topics, the theories and absurdities of Greek philosophy, the immoral character of the pagan deities, and the purity of Christian doctrine and practice.[7] If the Acts of the Apostles had been composed in the second century, the address of St. Paul to the Athenians would have been very different from what it is, and must necessarily have partaken of those characteristics which we find common to all the numerous treatises addressed to the heathen world of that date. If the Acts were written in the second century, why does not the writer put arguments into St. Paul's mouth like those which were current among the Christian apologists of that time? The philosophical argument of Aristides, which is followed by Justin Martyr[8] and the later apologists, when contrasted with the simplicity of St. Paul, is a conclusive proof of the early date of the composition of the Acts.[9] But this is not the only argument of this kind which modern research furnishes. Aristides shows us what the character of Christian controversy with the pagans was in the generation succeeding the Apostles. We can draw the same conclusion when we examine Christian controversy as carried on against the Jews of the same period.