Beside this _Romanus populus_, which constituted the ruling class under kings, was another body, made up of conquered people. In early times their number was small, nor did they appear as a distinct class until the reign of Tullus Hostilius. After the subjection of Alba, the head of the Latin Confederacy, great numbers were transferred to Rome, and received settlements on the Caelian Hill, and were kept under submission to the patricians. As the Roman conquests extended, their numbers increased, until they formed the larger part of the population. They were called _plebs_, or commonalty, and had no political privileges whatever. They had not even the right of suffrage; but they were enrolled in the army, [Footnote: Liv., i. 33. Dionys., iii. 31. ] and made to bear the expenses of the state. At first they were not allowed to intermarry with the patricians. Their oppression provoked resistance. The struggle which ensued is one of the most memorable in Roman history. The haughty oligarchy were obliged gradually to concede rights. These rights the _plebs_ retained. First they gained a law which prevented patricians from taking usurious interest. They secured the appointment of tribunes for their protection. Soon after they had the right of summoning before their own _Comitia tributa_ any one who violated their rights. In 449 they had influence sufficient to establish the Connubium, by which they could intermarry with patricians. In 421 the plebeians were admitted to the quaestorship. Then, after a fierce contest, they were made decemvirs. Their next right was the dignity of the consulship, and led to the dictatorship. In 351 they secured the censorship, and in 336 the praetorship. Political distinctions now vanished. The possession of a share of the great offices created powerful families, and these were incorporated with the aristocracy. The great privilege of securing tribunes was the first step to political power, and the most important in the constitutional history of the state. And it was the tribunes who gradually usurped the greatest powers. They assumed the right, in 456, of convoking even the Senate. They also had the right to be present in the deliberations of the Senate; as their persons were inviolable, they interceded against any action which a magistrate might undertake during his term of office, and even a command issued by a praetor. They could compel the Senate to submit a question to a fresh consultation, and ultimately compelled the consuls to appoint a dictator. Their power grew to such a height that they acquired the right of proposing to the _Comitia tributa_, or the Senate, measures on nearly all the important affairs of the state, and finally were elected from among the Senators themselves. [Sidenote: Advancement of Plebeians.]