In the Roman family, the husband and father were the head of the family. “Paternal authority” (patria potestas) lasted as a rule for life. It died out only with the death patris familias. Then the wife of the deceased (if she was subject to his authority), his children (but not grandchildren) and further descendants became persons sui iuris ([persons] of their right).
It is worth mentioning that the children must have come from a valid Roman marriage, as well as grandchildren and great-grandchildren.
In what situations, however, could paternal authority over a family member expire if pater faimilias was alive? In case when:
a family member has lost citizenship (capitis deminutio media). The patria potestas could only be Roman citizens.
a family member has lost his freedom (capitis deminutio maxima). A slave could not be the subject of any rights.
the child obtained a high priestly position (e.g. became a priestess of Vesta, a priest of Jupiter) or a high official position (e.g. became a praetorian prefect).
himself pater familias abolished paternal authority by emancipating.