*The urban proletariat.* Another difficulty was destined to arise from the growth of a turbulent mob in Rome itself. This was in large measure due to Rome’s position as the political and commercial center of the Mediterranean world. By the end of this period of expansion the city had a population of at least half a million, rivalling Alexandria and Antioch, the great Hellenistic capitals. Although not a manufacturing city, Rome had always been important as a market, and now her streets were thronged with traders from all lands, and with persons who could cater in any way to the wants and the appetites of an imperial city. There was a large proportion of slaves belonging to the mansions of the wealthy, and of freedmen engaged in business for themselves or for their patrons. Hither flocked also the peasants who for various reasons had abandoned their agricultural pursuits to pick up a precarious living in the city or to depend upon the bounty of the patron to whom they attached themselves. Owing to the slowness of transportation by land and its uncertainties by sea, the congestion of population in Rome made the problem of supplying the city with food one of great difficulty, since a rise in the price of grain, or a delay in the arrival of the Sicilian wheat convoy would bring the proletariat to the verge of starvation. And upon the popular assemblies the presence of this unstable element had an unwholesome effect. Dominated as these assemblies were by those who resided in the city, their actions were bound to be determined by the particular interests and passions of this portion of the citizen body. Furthermore, in the _contiones_ or mass meetings for political purposes, non-citizens as well as citizens could attend, and this afforded a ready means for evoking the mob spirit in the hope of overawing the Comitia. This danger would not have been present if the Roman constitution had provided adequate means for policing the city. As it was, however, beyond the magistrates and their personal attendants, there were no persons authorized to maintain order in the city. And since the consuls lacked military authority within the _pomerium_, there were no armed forces at their disposal.