With the commencement of the fifth century, <small>A.D.</small>, began the irruption of Barbarians. Attila’s Huns swept like a scourge over Europe, while the German tribes conquered the provinces in turn and occupied them. In 455 Rome was sacked by the Vandals. In 476 Odoacer was proclaimed by his troops King of Italy, and thus the Western part of the Empire was finally separated from the Eastern. This is the date selected to mark the “Fall” of the Roman Empire. Meanwhile the steady decline of the power of the emperors had been long in process and was accompanied by a corresponding increase in the power of the Popes. Henceforth, during the “Dark Ages” of civil confusion, the influence and authority of the Church were the chief sources of social as well as religious organisation. * * * * * The Roman ideal of civilisation received its most characteristic architectural expression in the several fora, beginning with the oldest--the Forum Romanum. From ancient times it was the heart of the city; the centre of civil activity; the scene of some of the most stirring incidents in the growth of Rome; in later times the nucleus of the pomp and pride of the Empire. Here at some time was erected a cylindrical monument in three tiers, the Umbilicus or Navel of Rome, and hard by it stood the Milliarium, a marble column, sheathed in bronze and inscribed with the names and distances of the chief cities on the great trunk-roads that radiated throughout the Empire from the thirty-seven gates of Rome. Between these two monuments extended a platform, decorated with the bronze beaks of conquered vessels and hence called the Rostra, from which any citizen could speak who had aught to say concerning the commonweal. For it faced the Comitium or open space, which from earliest times had been the meeting place of the General Assembly of the people. It is true that the voice of the people was too often dominated by the Patrician class whose Curia or Senate House overlooked the Comitium; but the Comitium continued to represent, at least, the theory of Roman Government and to be the veritable nucleus of the Roman Forum. Since the Forum embodied the ideals and the progress of Rome, its architectural aspects were continually changing throughout the more than one thousand years of Rome’s vicissitudes. But without attempting to follow these changes--many of which are shrouded in obscurity--let us try to picture the Forum in its general aspects and particularly as the embodiment of the Roman ideal.