Modern physicians will, at first thought, be disposed to wonder how men as clever as many of these physicians were could have split up into separate and more or less antagonistic sects because of such apparently trivial differences of opinion. It must be remembered, however, that these men were groping in comparative darkness whenever they tried to advance their knowledge of pathology, and that in this imperfect light many things seemed of much greater importance than they appeared to be in the brighter light of later centuries. It is only fair, therefore, to withhold criticism and to ask ourselves whether this strong desire on the part of those men to advance their knowledge of pathology--a desire which manifested itself in the formation of sects--was not in reality an evidence of the great vitality of Greek medicine on Roman soil in those early centuries. The remarks made above with regard to the Dogmatists and the Empirics apply in a general manner to the sects known as the Methodists and the Eclectics, a sufficiently full account of which has been given in the preceding chapter.[38] CHAPTER XIV WELL-KNOWN MEDICAL AUTHORS OF THE EARLY CENTURIES OF THE CHRISTIAN ERA There were four men who were not especially identified with any of the sects described in the preceding chapters, and yet who occupied, as authors of medical treatises, very prominent places in the history of medicine of the period or epoch which we have just been considering. They are Celsus, Scribonius Largus, Pliny the Elder and Dioscorides. These men lived during the first and second centuries A. D. and they therefore all belong strictly to the period which is designated in our scheme as the fourth epoch. I shall give here brief sketches of all of these writers and of their works. While Caelius Aurelianus, another important medical author, belonged to a much later period, I shall, for reasons of convenience, describe in the same chapter with the others the part which he played in the evolution of medicine.