vigilance and multiply its ordinances. The property of the family must be kept together as strictly as possible and for the longest possible time. The father is its sole master and arbiter; but on his death the patrimony is equally divided between sons and daughters. The _unity_ of the family must also be guarded and defended by the law, since there is serious danger that a woman marrying may carry away from the family an interest in the family property. She is accordingly subjected by the law to a perpetual tutelage which prevents her from disposing at will of her own property. On the death of her father the woman comes under the tutelage of the agnati. In Cicero's day, when as Vico has noted, the true significance of primitive Roman law had been lost, lawyers believed that this tutelage of women had been established on account of the weakness of the sex, _propter sexus infirmitatem_. But Gaius refers to this opinion as a plausible and prevalent error, and maintains that the restriction was instituted in the interest of the agnati, so that the woman, whose presumptive heirs they were, should have no power to alienate, diminish, or otherwise defraud them of their inheritance.[370] So long as the woman remained under the tutelage of her father, inasmuch as she had not yet inherited, the law allowed her to incur legal obligations. The danger for the family began when, on her father's death, she became an heir. It was from that precise moment, accordingly, that she came under the tutelage of her own heirs the agnati, and could no longer bind herself without their consent. This tutelage, therefore, became not merely a duty on the part of the agnati, but was also a right and privilege. Where the agnate was a minor, of weak mind, or otherwise incapacitated, he did not forfeit this right, but it had to be exercised by a third party. The tutor fixed the dowry to be given with the woman on her marriage; but the remainder of her patrimony had to be preserved intact, that it might return afterwards to the agnati. No woman could make a will, that she might not have it in her power to defraud the family. On passing _in manus viri_, the woman underwent a _capitis diminutio_. She entered another family, as it were, _loco filiæ_, and her new relations became her lawful heirs. Under these circumstances the law permitted her to make a testamentary disposition, whereby, notwithstanding her new relationships, she might restore her patrimony to her own original family.