Each frontier province had its little army, garrisoned in a permanent camp similar to a fortress. Merchants came to establish themselves in the vicinity, and the camp was transformed into a city; but still the soldiers, encamped in the face of the enemy, preserved their valor and their discipline. There were for three centuries severe wars, especially on the banks of the Rhine and of the Danube, where Romans fought fierce barbarians in a swampy country, uncultivated, covered with forests and bogs. The imperial army exhibited, perhaps, as much bravery and energy in these obscure wars as the ancient Romans in the conquest of the world. =Deputies and Agents of the Emperor.=--All the provinces belonged to the emperor[148] as the representative of the Roman people. He is there the general of all the soldiers, master of all persons, and proprietor of all lands.[149] But as the emperor could not be everywhere at once, he sent deputies appointed by himself. To each province went a lieutenant (called a deputy of Augustus with the function of prætor); this official governed the country, commanded the army, and went on circuit through his province to judge important cases, for he, like the emperor, had the right of life and death. The emperor sent also a financial agent to levy the taxes and return the money to the imperial chest. This official was called the "procurator of Augustus." These two men represented the emperor, governing his subjects, commanding his soldiers, and exploiting his domain. The emperor always chose them among the two nobilities of Rome, the prætors from the senators, the procurators from the knights. For them, as for the magistrates of old Rome, there was a succession of offices: they passed from one province to another, from one end of the empire to the other,[150] from Syria to Spain, from Britain to Africa. In the epitaphs of officials of this time we always find carefully inscribed all the posts which they have occupied; inscriptions on their tombs are sufficient to construct their biographies.