§28. The Roman was bound, therefore, to perform these acts of affection and piety so long as he lived himself, and bound no less to provide for their performance after his death by perpetuating his race and the family cult. A curse was believed to rest upon the childless man. Marriage was, therefore, a solemn religious duty, entered into only with the approval of the gods ascertained by the auspices. In taking a wife to himself the Roman made her a partaker of his family mysteries, a service that brooked no divided allegiance. He therefore separated her entirely from her father's family, and was ready in turn to surrender his daughter without reserve to the husband with whom she was to minister at another altar. The _pater familiās_ was the priest of the household, and those subject to his _potestās_ assisted in the prayers and offerings, the _sacra familiāria_. §29. But it might be that a marriage was fruitless, or that the Head of the House saw his sons die before him. In this case he had to face the prospect of the extinction of his family, and his own descent to the grave with no posterity to make him blessed. One of two alternatives was open to him to avert such a calamity. He might give himself in adoption and pass into another family in which the perpetuation of the family cult seemed certain, or he might adopt a son and thus perpetuate his own. He usually followed the latter course, because it secured peace for the souls of his ancestors no less than for his own. §30. Adoption.--The person adopted might be either a _pater familiās_ himself or, more usually, a _fīlius familiās_. In the case of the latter the process was called _adoptiō_ and was a somewhat complicated proceeding by which the natural parent conveyed his son to the other, the effect being to transfer the adopted person from one family to the other. The adoption of a _pater familiās_ was a much more serious matter, for it involved the extinction of one family (§29) in order to prevent the extinction of another. It was called _adrogātiō_ and was an affair of state. It had to be sanctioned by the _pontificēs_, the highest officers of religion, who had probably to make sure that the _adrogātus_ had brothers enough to attend to the interests of the ancestors whose cult he was renouncing. If the _pontificēs_ gave their consent, it had still to be sanctioned by the _comitia curiata_, as the adrogation might deprive the _gēns_ of its succession to the property of the childless man (§22). If the _comitia_ gave consent, the _adrogātus_ sank from the position of Head of a House to that of a _fīlius familiās_ in the household of his adoptive father. If he had wife and children, they passed with him into the new family, and so did all his property. Over him the adoptive father had _potestās_ as over a son of his own, and looked upon him as flesh of his flesh and bone of his bone. We can have at best only a feeble and inadequate notion of what adoption meant to the Romans.