One of the most fruitful branches of recent patristic study has been the effort to determine the relation between early Christian theology and Greek philosophy. Starting from the assumption that the affinities between the two were many and close, scholars have found themselves able to draw detailed inferences of literary and intellectual dependence, and in the case of many Christian authors to discover the exact sources from which they drew their philosophic ideas, or at least to assign these to some contemporary school. Without such work an accurate estimate of the fathers' views and ways of thinking is impossible, but it must be remembered that an author is not explained, or even fairly represented, by showing how much he may have derived from others, for in the last analysis his finished thought is his own, however extensive the foreign material employed in its construction. It is not, therefore, at the end but at the beginning of his work that the historian of thought can expect most help from the investigation of sources, since even an author who differs from his contemporaries in his answers to current problems must usually begin by seeing them as they do. The background of an author's thought must have supplied the starting point for many of his ideas.