In every department of the State the same principle of hereditary bondage was applied to the lower grades of the service, and even in some cases to officials of considerable rank. Here, however, a release was conceded to those who could provide an acceptable substitute, a condition but rarely possible to fulfil.[830] Armourers, mintmen, weavers, dyers, purple-gatherers, miners, and muleteers, in government employ[831] could neither resign their posts nor even intermarry[832] with associates on a different staff, or the general public, unless under restrictions which were almost prohibitive. Within the same category were ruled the masters or owners of freight-ships,[833] chartered to convey the annones and tributes, of which the Alexandrian corn-fleet[834] constituted the main section. Those addicted to this vocation in the public interest were necessarily men of some private means, as they were obliged to build and maintain the vessels at their own expense; but they were rewarded by liberal allowances, and were almost exempt in respect of the laws affecting the persons and property of ordinary citizens. The lot of this class of the community appears to have been tolerable, and was even, perhaps, desirable,[835] but that of the Decurions, the members of the local senates, was absolutely unbearable.[836] In relation to their fellow townsmen their duties do not seem to have been onerous, but as collectors of the revenue they were made responsible for the full precept levied four-monthly on each district, and had to make good any deficiency from their own resources.[837] As natives of the locality to which their activities were constrained, their intimate knowledge of the inhabitants was invaluable to the government in its inquisitorial and compulsive efforts to gather in the imposts; and, subordinated to the Imperial officials resident in, or on special missions to, the provinces, they became consequently the prime object of their assaults when dealing with the defaulting tributaries. In view of such hardships, municipal dignities and immunities were illusory; and, as the local senates were very numerous, there were few families among the middle classes, from whom those bodies were regularly replenished, whose members did not live in dread of a hereditary obligation to become a Decurion. In every ordinary sphere of exertion, not excepting the Court, the Church, or the army, men, long embarked on their career, were liable to receive a mandate enjoining them to return to their native town or village in order to spend the rest of their lives in the management of local affairs.[838] Occupation of the highest offices of State, or many years’ service in some official post, could alone free them from the municipal bond.[839]