We may learn from the erection of the Column of Phocas, in A.D. 608, that the Forum was then unencumbered with soil. Rome having been at that time deserted for a long period by its emperors, its principal monuments began to fall into decay, the Romans themselves hastening on the work for the sake of the marble; the steady hand of time, allied with the luxuriant vegetation, working slowly but surely, added to the _débris_; whilst deposits from the Tiber floods, the wind, and the wash of the rain-shed, helped still more to fill in the valleys. During a long course of years Rome was almost abandoned; the streets remained unswept, and the rubbish of the city collected upon them. At length a new life sprang up, and to the dust of ages was added the refuse of building materials for the new city, till in the year 1650 we have the Forum presented to us on a level with the modern streets, under the name of the Campo Vaccino (the Cow-field); and thus was the Forum filled up. Such are the fluctuations of worldly splendour! [Illustration: PLAN OF THE ROMAN FORUM] EXTENT OF THE FORUM. The Forum was not, as many have supposed, a building, but an open space surrounded with buildings, the whole forming the Forum. It was 260 yards long, and 55 yards wide at the bottom. The top, under the Capitol, was 140 yards wide. The temples were built on lofty platforms (_podia_), to give them a more commanding appearance. [Illustration: THE ROMAN FORUM, LOOKING TOWARDS THE CAPITOLINE HILL. 1. The Temple of Castor and Pollux. 2. The Basilica Julia. 3. Shrine of Venus. 4. Temple of Saturn. 5. Tabularium. 6. Arch of Severus. 7. Mamertine Prison. 8. Column of Phocas. 9. Temple of Vespasian. 10. Temple-tomb of Cæsar. 11. Senate House. 12. Shop. 13. Via Sacra. 14. Bases. 15. Pedestal of Domitian's Statue. 16. Puteal. 17. Marsyas. 18. Attus Navius. 19. Old Rostra. 20. Reliefs of M. Aurelius. 21. Site of Statue. 22. Portico of the 12 Gods. 23. Clivus Capitolinus. 24. Tarpeian Rock. 25. Tower of Capitol. 26. Vicus Tuscus. 27. Street of Ox Heads. 28. Curtian Lake.] TEMPLE OF CASTOR AND POLLUX. Founded by Aulus Posthumius, A.U.C. 268-74, in commemoration of the battle of Lake Regillus. It was afterwards rebuilt by Lucius Metellus. "Tiberius dedicated the Temple of Castor and Pollux, which had been rebuilt out of the spoils of the German war, in his own and his brother's name" (Suetonius, "Tiberius," xx.). "Caligula converted it into a kind of vestibule to his house" (_Ibid._, "Caligula," xxii.).