Now, as long as the _civis Romanus_, as a prerogative of his position, paid no tax, his right of residence was unqualified. When he too had to submit to a direct tax, the place where he resided became a matter of prime importance. The tax that was imposed upon any given locality could be met only if all those subject to tax, living there, paid their dues. Consequently those who by birth were domiciled there could not remove themselves without lessening to that extent the power of that district to meet its state obligations. At first, to be sure, this cannot have been a matter of first-rate importance. Changes of domicile after all were rare, and took place principally among the wealthier classes, a fact that made it easy to insure that no loss would accrue to the community abandoned. But as conditions of ordinary living deteriorated, the practice of deserting one’s legal residence became more frequent, and needed the intervention of the central authorities, since the local magistrate had no jurisdiction whatever beyond the strictly circumscribed limits of his commune. As soon as it was possible for a commune to claim from its members, wherever they happened to be, their contribution to the communal tax, there arose the corollary that for all practical purposes the tax-paying member might not leave the place where his tax was due. The _colonatus_ had been applied to the urban laborer.
But the chaining of the individual to his commune was not sufficient unless his paying power was maintained. The same motives that impelled men to evade their fiscal duties by change of domicile, would make them idle and sullen paupers in the places where they were forced to remain. It was a part of the state system which the Severan emperors introduced to make the paying power of the citizen certain by means of the compulsory guilds.[390] These latter were natural outgrowths of former voluntary associations. The formation of guilds of laborers, either free or consisting partly of freemen and slave laborers, was as old as the state itself. The evident superiority of training which such groups insured alone justified them. From time to time certain privileges and exemptions were conferred upon them—always in return for definite state functions[391] which they took upon themselves as well as the industrial functions which were their reason for existence. Indeed, in the municipal towns the _collegiati_, or members of these publicly sanctioned industrial guilds, formed an order of citizenship second only to that of the decurions, or municipal senate.