No example remains of Etruscan temples, but Vitruvius has described them. The plan was nearly square and the cella was divided into three chambers, since it was in groups of three that the Etruscans worshipped their deities. The columns represented in rude form the Doric order, set so far apart that it is concluded they were surmounted by beams of timber. A further distinction of the Etruscan temple, adopted by the Romans, was the replacing of the stylobate by a _podium_. This was a continuous pedestal or low wall on which the columns were carried. It was approached in front by a flight of steps, enclosed between the prolongation of the side-walls of the podium. The most famous example was the Temple of Jupiter on the Capitoline Hill, dedicated <small>B.C.</small> 509, which contained three chambers, for the statues of Jupiter, Minerva, and Juno. It was destroyed by fire <small>B.C.</small> 83, and rebuilt by Sulla, who brought over for the purpose some of the Corinthian columns from the temple of Zeus Olympius in Athens. (See p. 122.) Until recently the great sewer, or “Cloaca Maxima,” of Rome, constructed about <small>B.C.</small> 578, has been attributed to the Etruscans and considered a proof that they introduced the use of the arch to the Romans. But in 1903, when excavating the Forum, Commendatore Boni proved that the drain was originally uncovered and that the arch, which consists of three rings of voussoirs, each 2 feet 6 inches high, was added at the end of the Republic. “Thus the honour, not of discovering the arch, for it was known in the East, as we noted, but of popularising its use, does not belong to the Etrurians, though they did use it at a comparatively late time for city gates, as at Volterra.” (Encyclopædia Britannica, “Etruria.”) * * * * * Following Augustus, the emperors under whom Roman architecture chiefly flourished were: Nero (<small>A.D.</small> 54-69), Vespasian (69-79), Trajan (98-117), Hadrian (137-138), Septimus Severus (193-211), Caracalla (211-217), and Diocletian (284-305). By Constantine (306-337) were inaugurated two changes of policy, which affected the destinies of the world. For by granting toleration to all religions he raised Christianity to equal footing with paganism and thus paved the way for the power of the Church; and in establishing his capital at Byzantium took the first step in the partition of the Empire into East and West. Aided by his vigorous efforts, architecture, which had declined, enjoyed a measure of revival, in which, as we shall see later, the Church began to play a conspicuous part.