In this state the art passed into the hands of the masters of the world, and they inaugurated a new era in architecture. The art was still essentially Greek, although the Romans derived their first knowledge from the Etruscans. The Cloaca Maxima was built during the reign of the second Tarquin--the grandest monument of the reign of the kings. It is not probable that temples and other public buildings were either beautiful or magnificent until the conquest of Greece, when Grecian architects were employed. The Romans adopted the Corinthian style, which they made even more ornamental, and by the successful combination of the Etruscan arch with the Grecian column, laid the foundation of a new and original style, susceptible of great variety and magnificence. They entered into architecture with the enthusiasm of their teachers, but, in their passion for novelty, lost sight of the simplicity which is the great fascination of a Doric Temple. "And they deemed that lightness and grace were to be attained not so much by proportion between the vertical and the horizontal, as by the comparative slenderness of the former. Hence we see a poverty in Roman architecture in the midst of profuse ornament. The great error was a constant aim to lessen the diameter, while they increased the elevation, of the columns. Hence the massive simplicity and severe grandeur of the ancient Doric disappear in the Roman, the characteristics of the order being frittered down into a multiplicity of minute details." [Footnote: Memes, _Sculpture and Architecture._] And when they used the Doric at all, they used the base, which was never done at Athens. They also altered the Doric capital, which cannot be improved. Again, most of the Grecian Doric temples were peripteral, that is, were surrounded with pillars on all the sides. But the Romans did not build with porticoes even on each front, but only on one, which had a greater projection than the Grecian. They generally are projected three columns. Many of the Roman temples are circular, like the Pantheon, which has a portico of eight columns projected to the depth of three. Nor did the Romans construct hypaethral temples, or uncovered, with internal columns, like the Greeks. The Pantheon is an exception, since the dome has an open eye; and one great ornament of this beautiful structure is in the arrangement of internal columns placed in the front of niches, composed with antae, or pier- formed ends of walls, to carry an entablature round under an attic on which the cupola rests. They also adopted coupled columns, broken and recessed entablatures, and pedestals, which are considered blemishes. They again paid more attention to the interior than to the exterior decoration of their palaces and baths, as we may infer from the ruins of Adrian's villa at Tivoli, and the excavations of Pompeii.