After Aëtius came Alexander of Tralles, from another of these towns of Asia Minor that we would consider insignificant, sometimes termed Trallianus for this reason. He must be reputed one of the great independent thinkers in medicine whose writings have deservedly attracted attention not only in his own time, but long afterwards in the Renaissance period, and with whose works everyone who cares to know anything about the development of medical history must be familiar. One detail of his life has always seemed to me to correct a whole series of misapprehensions with regard to the earlier Middle Ages. Alexander was one of five brothers, all of whose names have come down to us through nearly 1,500 years because of what they accomplished at the great Capital of the East. The eldest of them was Anthemios, the architect of the great Church of Santa Sophia. A second brother was Methrodoros, a distinguished grammarian and teacher at Constantinople. A third brother was a prominent jurist in the Imperial Courts of the capital; while a fourth brother, Dioscoros, was, like Alexander, a physician of repute, but remained in his birthplace Tralles, and acquired a substantial practice there. There is sometimes the feeling that at this time in the world's history, the end of the sixth and the beginning of the seventh century, men had but little initiative, and above all very little power of achievement in the intellectual order. Anyone who knows Santa Sophia in Constantinople, however, will recognize at once that the architect who conceived and superintended the construction of that great edifice was a genius of a high order, not lacking in initiative, but on the contrary possessed of a wonderful power of original accomplishment. No greater constructive work, considering all the circumstances, has perhaps ever been successfully planned and executed. It would scarcely be expected that the brother of the man who conceived and finished Santa Sophia would, if he set out to write a textbook of medicine, make an egregious failure of it. Surely his work would not be all unworthy of his brother's reputation, and the family genius should lift him up to important accomplishment. This is literally what we find true with regard to Alexander. After years of travel which led him into Italy, Gaul, Spain, and Africa, he settled down at Rome, and practised medicine successfully until a very old age, and probably lectured there, for some of his books are in the form of lectures. Fortunately for us, he committed his knowledge and his experience to writing, which has come down to us.