In life as in nature there are variations of current and of coast formation. There are limits, of course, within which this caveat holds good; but, provided the interval of time is not too great, the view that St. Luke could begin to write in ignorance of a tradition already known elsewhere is not self‐condemned. After all, St. Luke himself had access to much tradition which presumably was unknown to the First Evangelist (witness St. Luke’s special matter). Concerning the length of time we can allow the Virgin Birth tradition to have been already known elsewhere, when St. Luke began to write, there is room for difference of opinion. If, as we have contended, he became acquainted with it in the process of writing or immediately afterwards, the period can scarcely have been considerable. Perhaps it ought to be estimated in months rather than in years, but to say more would be idle speculation. _The farthest point therefore to which we can trace the existence of the Virgin Birth as a public tradition is some little time previous to the composition of the Third Gospel._ (3) It is a perfectly fair assumption to make that the public tradition must have had a _private_ vogue before, and perhaps for some time before, it became public property. This view becomes especially probable in the light of what we have just seen, viz. that the spread of the public tradition among the primitive Christian communities covered an appreciable period of time. The question of the historical truth of the Virgin Birth is precisely the question of how far back the private tradition can be traced; whether it can go back to Mary the mother of Jesus, and whether satisfactory reasons can be given for a silence which extends beyond the period covered by the Pauline Epistles and the Second Gospel, and is broken only at last in the interval which shortly preceded the composition of the Gospels of Mt. and Lk. In this lies the real historical problem. _Can the theory of a private authoritative tradition be vindicated?_ There are several questions which bear upon this problem. They are: (1) The question of the date of the First and of the Third Gospels; (2) The extent to which the credibility of the Gospels permits of the possibility of error; (3) The Alternative Theories of the origin of belief in the Virgin Birth; (4) The theological aspect of the tradition. II. The Date of the Gospels in Relation to the Virgin Birth Tradition The relation in which the question of _the Date of the Gospels_ stands to the results reached is sufficiently clear. If we could fix the time when Mt. and Lk. were written, we could determine within comparatively narrow limits when the Virgin Birth tradition first gained currency. A conclusion upon this point would materially affect our estimate of the historical value of the tradition.