So much as this we should expect from the constitution of theearliest Roman society, for we can hardly form a notion of theprimitive family group unless we suppose that its members broughttheir earnings of all kinds into the common stock while they wereunable to bind it by improvident individual engagements. The trueenigma of the Patria Potestas does not reside here, but in theslowness with which these proprietary privileges of the parentwere curtailed, and in the circumstance that, before they wereseriously diminished, the whole civilised world was broughtwithin their sphere. No innovation of any kind was attempted tillthe first year of the Empire, when the acquisitions of soldierson service were withdrawn from the operation of the PatriaPotestas, doubtless as part of the reward of the armies which hadoverthrown the free commonwealth. Three centuries afterwards thesame immunity was extended to the earnings of persons who were inthe civil employment of the state. Both changes were obviouslylimited in their application, and they were so contrived intechnical form as to interfere as little as possible with theprinciple of Patria Potestas. A certain qualified and dependentownership had always been recognised by the Roman law in theperquisites and savings which slaves and sons under power werenot compelled to include in the household accounts, and thespecial name of this permissive property, Peculium, was appliedto the acquisitions newly relieved from Patria Potestas, whichwere called in the case of soldiers Castrense Peculium, andquasi-castrense Peculium in the case of civil servants. Othermodifications of the parental privileges followed, which showed aless studious outward respect for the ancient principle. Shortlyafter the introduction of the Quasicastrense Peculium,Constantine the Great took away the father's absolute controlover property which his children had inherited from their mother,and reduced it to a usufruct, Or life-interest. A few morechanges of slight importance followed in the Western Empire, butthe furthest point reached was in the East, under Justinian, whoenacted that unless the acquisitions of the child were derivedfrom the parent's own property, the parent's rights over themshould not extend beyond enjoying their produce for the period ofhis life. Even this, the utmost relaxation of the Roman PatriaPotestas, left it far ampler and severer than any analogousinstitution of the modern world. The earliest modern writers onjurisprudence remark that it was only the fiercer and ruder ofthe conquerors of the empire, and notably the nations ofSclavonic origin, which exhibited a Patria Potestas at allresembling that which was described in the Pandects and the Code.
All the Germanic immigrants seem to have recognised a corporateunion of the family under the mund, or authority of a patriarchalchief; but his powers are obviously only the relic of a decayedPatria Potestas, and fell far short of those enjoyed by the Romanfather. The Franks are particularly mentioned as not having theRoman Institution, and accordingly the old French lawyers, evenwhen most busily engaged in filling the interstices of barbarouscustom with rules of Roman law, were obliged to protectthemselves against the intrusion of the Potestas by the expressmaxim, Puyssance de pere en France n'a lieu. The tenacity of theRowans in maintaining this relic of their most ancient conditionis in itself remarkable, but it is less remarkable than thediffusion of the Potestas over the whole of a civilisation fromwhich it had once disappeared. While the Castrense Peculiumconstituted as yet the sole exception to the father's power overproperty, and while his power over his children's persons wasstill extensive, the Roman citizenship, and with it the PatriaPotestas,were spreading into every corner of the empire. EveryAfrican or Spaniard, every Gaul, Briton, or Jew, who receivedthis honour by gift, purchase, or inheritance, placed himselfunder the Roman Law of Persons, and, though our authoritiesintimate that children born before the acquisition of citizenshipcould not be brought under Power against their will, childrenborn after it and all ulterior descendants were on the ordinaryfooting of a Roman filius familias. It does not fall within theprovince of this treatise to examine the mechanism of the laterRoman society but I may be permitted to remark that there islittle, foundation for the opinion which represents theconstitution of Antoninus Caracalla conferring Roman citizenshipon the whole of his subjects as a measure of small importance.
However we may interpret it, it must have enormously enlarged thesphere of the Patria Potestas, and it seems to me that thetightening of family relations which it effected is an agencywhich ought to be kept in view more than it has been, inaccounting for the great moral revolution which was transformingthe world.