The two ideas underlying the Roman conception of the family are those of unity and power, and both are singularly perfect. The former is attained, and the latter exercised, by the head. It is through him alone that the family is a person; and the authority he wields over the members subordinated to his will is called _potestas_.[75] The power over the children is described as _patria potestas_, as over the slave it is _dominica_. The two do not differ legally; there is only a difference of ethical signification. Under this _potestas_ fall, firstly, the children, both sons and daughters; secondly, the descendants of these children; thirdly, the wife united to her lord by a form of marriage which makes her a member of the family; fourthly, the wives of the sons and grandsons who have entered the _familia_ by a similar binding form of marriage. There is a complete absence of independent rights amongst these members of the household. As to the wife, any property that she might be possessed of, or which she acquired, passed absolutely into the power of her husband. He was responsible for her conduct and possessed the right of moderate chastisement. Severer punishment for wrongs to the household required the support of the family council. No legal action might be brought by the woman against her lord, for they were not two personalities, but one. He might divorce her on good grounds,[76] but if she were married under a form which subjected her to his power, she had no legal means of freeing herself from his tyrannous rule. Her position is that of a daughter and she inherits equally with her children. The decision as to whether the child of the marriage was to be reared (_liberi susceptio_) belonged to the father, but was, in the interest of the state, subjected at an early period to certain modifications. The “laws of Romulus”—that is, the early pontifical law—enjoined the rearing of every male child and of the first-born of the females; the exposure of offspring was to receive the assent of five neighbours,[77] and disobedience of these canons was to be visited with severe penalties on the parent who neglected the welfare of the state. The children and their descendants are never released from the absolute rule of the father as long as he lives. They cannot own property; for all that they acquire belongs to the common stock and is at the disposal of the head of the family. At best the father might permit the son, as he might permit the slave, to employ his own earnings for his own use. This is the _peculium_. Yet the grant is a mere concession, and one which may be withdrawn at any moment. If the son dies it lapses to the father; if the father dies it falls to the heir.