GROWTH OF ROME UNDER THE TARQUINS.--The Tarquins extended their authority over the whole of Latium. The position of supremacy thus given Rome was naturally attended by the rapid growth in population and importance of the little Palatine city. The original walls soon became too strait for the increasing multitudes; new ramparts were built--tradition says under the direction of the king Servius Tullius--which, with a great circuit of seven miles, swept around the entire cluster of the Seven Hills. A large tract of marshy ground between the Palatine and Capitoline hills was drained by means of the Cloaca Maxima, the "Great Sewer," which was so admirably constructed that it has been preserved to the present day. It still discharges its waters through a great arch into the Tiber. The land thus reclaimed became the Forum, the assembling-place of the people. Upon the summit of the Capitoline Hill, overlooking the Forum, was built the famous sanctuary called the Capitol, or the Capitoline temple, where beneath the same roof were the shrines of Jupiter, Juno, and Minerva, the three great national deities. Upon the level ground between the Aventine and the Palatine was laid out the Circus Maximus, the "Great Circus," where were celebrated the Roman games. [Illustration: VIEW OF THE CAPITOLINE, WITH THE CLOACA MAXIMA. (A Reconstruction.)] NEW CONSTITUTION OF SERVIUS TULLIUS.--The second king of the Etruscan house, Servius Tullius by name, effected a most important change in the constitution of the Roman state. He did here at Rome just what Solon at about this time did at Athens (see p. 120). He made property instead of birth the basis of the constitution. The entire population was divided into five classes, the first of which included all citizens, whether patricians or plebeians, who owned twenty _jugera_ (about twelve acres) of land; the fifth and lowest embraced all that could show title to even two jugera. The army was made up of the members of the five classes; as it was thought right and proper that the public defence should be the care of those who, on account of their possessions, were most interested in the maintenance of order and in the protection of the boundaries of the state. The assembling-place of the military classes thus organized was on a large plain just outside the city walls, called the Campus Martius, or "Field of Mars." The meeting of these military orders was called the _comitia centuriata_, or the "assembly of hundreds." [Footnote: This assembly was not organized by Servius Tullius, but it grew out of the military organization he created.] This body, which of course was made up of patricians and plebeians, gradually absorbed the powers of the earlier patrician assembly (_comitia curiata_).