In the year 64 the capital of the Roman Empire was, it is true, a large and splendid city and an "epitome of the world," but it had not yet reached either its zenith of splendour or its maximum, of size. Many of the largest and most sumptuous structures of which we possess the records, and in most cases the ruins, were not yet built or even contemplated. There was no Colosseum; there were no Baths of Trajan, Caracalla, or Diocletian. The Column of Trajan, still soaring in the Foro Traiano, and of Marcus Aurelius, now so conspicuous in the Piazza Colonna, are of a later date. So also are the three great triumphal arches which are still standing--those of Titus, Severus, and Constantine. The Mausoleum of Hadrian, now stripped of its outward magnificence of marble and sculpture, and known as the Castle of Sant' Angelo, was not built for two generations. On the Palatine Hill the palaces of the Caesars were wide and lofty, but not more than half so spacious and imposing as they became by the end of the following century. Down in the Forum there stood no Basilica of Constantine; the place of several later temples and shrines was occupied by edifices of less dignity; many columns and statues, and much ornament of gilt or marble, were still to come. Beside and beyond the two embellished public places which had been added to the public comfort and convenience by Julius Caesar and Augustus, and which were known respectively as the Julian and the Augustan Forum, lay only the houses of citizens or streets of shops. Up from the Forum towards the later Arch of Titus and the Colosseum, the "Upper Sacred Way" ran as but a narrow road between buildings for the most part of ordinary character, principally shops catering for luxury. It was later by two centuries and a half that this street was converted into a broad avenue forming a worthy approach to the "hub of the universe."