A new dynasty succeeded this king, who reigned twenty-four years; that of the Tarquins, an Etrurian family of Greek extraction, which came from Corinth, the cradle of Grecian art, celebrated as the birth-place of painting and for its works of pottery and bronze. Tarquinius Priscus constructed the Cloaca Maxima, that vast sewer which drained the Forum and Velabrum, and which is regarded by Niebuhr as one of the most stupendous monuments of antiquity. It was composed of three semicircular arches inclosing one another, the innermost of which had a diameter of twelve feet, large enough to be traversed by a Roman hay-cart. [Footnote: Arnold, _Hist. of Rom._, vol. i. p. 52.] It was built without cement, and still remains a magnificent specimen of the perfection of the old Tuscan masonry. Along the southern side of the Forum this enlightened monarch constructed a row of shops occupied by butchers and other tradesmen. At the head of the Forum and under the Capitoline he founded the Temple of Saturn, the ruins of which attest considerable splendor. But his greatest work was the foundation of the Capitoline Temple of Jupiter, completed by Tarquinius Superbus, the consecrated citadel in which was deposited whatever was most valued by the Romans. [Sidenote: Accession of Servius Tullius.] During the reign of Servius Tullius, who succeeded Tarquin B.C. 578, the various elements of the population were amalgamated, and the seven hills, namely, the Palatine, the Capitoline, the Quirinal, the Caelian, the Viminal, the Esquiline, and the Aventine, were covered with houses, and inclosed by a wall about six miles in circuit. A temple of Diana was erected on the Aventine, besides two temples to Fortune, one to Juno, and one to Luna. Servius also dedicated the Campus Martius, and enlarged the Mamertine Prison by adding a subterranean dungeon of impenetrable strength. [Sidenote: Tarquinius Superbus.] On the assassination of Servius Tullius, B.C. 535, his son-in-law, Tarquinius Superbus, usurped the power, and did much for the adornment of the city. The Capitoline Temple was completed on an artificial platform, having a triple row of columns in front, and a double row at the sides. It was two hundred feet wide, having three cells adjoining one another, the centre appropriated to Jupiter, with Juno and Minerva on either hand. The temple had a single roof, and lasted nearly five hundred years before it was burned down, and rebuilt with greater splendor. [Sidenote: Rome under the early consuls.] [Sidenote: Roman roads.]