Also, a son could marry, for Roman law had never recognized monogamous sexual relationships between slaves. Sons could also inherit property, and this possibility of inheritance was another instrument of power used by fathers against their sons. A son who had been emancipated could marry without the consent of his father. The relationship between father and son was known as "patria potestas" or the rights given to a father by virtue of his paternity. "The foundation of the patria potestas was a Roman marriage, and the birth of a child gave it full effect." (Smith, 1875)
Although the Patria Potestas not viewed equivalent to a dominica potestas, or the ownership of the child analogous to the master slave relationship, the father had the power of life and death and liberty over his son as a member of his family, could sell the son and so bring him to a state of slavery, was liable for the debts of his child, could give his child in adoption, and emancipate a child at his pleasure, could disinherit his son, could substitute another person as heir in the place of his son, and he could by his will appoint him a tutor to another family. In short, ownership existed, in the view of some legal scholars in a de facto, if not de jure manner. (Smith, 1875)
Unlke a slave, however, the temporary incapacity of an unemanicpated child was not a permanent incapacity of acquiring legal rights. The child could acquire property by contract unlike a slave, but every thing that he acquired, was acquired for his father until the child came of age. The child had the right to marry unlike aslave, "like any Roman citizen who was sui juris, but these legal capacities brought to him no present power or ownership. His marriage[unlike a slave] with his father's consent was legal (justum), but...his wife came into the power of his father, and not into the power of the son."(Smith, 1875)
The son's children were in all cases in the power of their grandfather, when the son was still under his father's power. The son could also divorce his wife "but only with his father's consent," and the guiding principle of Roman law, for administering justice pertaining to both slaves and sons was that a paterfamilias ought to be enriched by his sons and slaves, not made poorer by their presence, in short that their labor was designed to improve the paterfamilias' lot, rather than detract from it.
Smith, William. "Patria potesta. A Dictionary of Greek and Roman Antiquities, John Murray, London, 1875. [7 Dec 2007] http://penelope.uchicago.edu/Thayer/E/Roman/Texts/secondary/SMIGRA*/Patria_Potestas.html
Does the treatment of the institution of marriage in Roman law provide any insights into the way in which changes in society give rise to changes in law?
In ancient Rome, marriages were arranged between the bride's father and her husband, or the father of her husband, indicating the power of the male head of household. "There were three types of marriage in ancient Rome; by usus (cohabitation), by confarreatio (religious ceremony), and by coemptio (purchase). Marriage by usus always required the woman to be married with manus," whereby the father of the bride relinquished his control over his daughter to the new husband, or to the paterfamilias. (Morin, 2006) "Usus also required that the woman had to remain and stay in her husband's house for one year, cohabitating with him, assuming the position of daughter in the family. Marriage by confarreatio involved a religious ceremony. This type of marriage was usually reserved for the wealthy. Religious wedding ceremonies were expensive and included difficult rituals. A woman in this situation was married with manus. "(Morin, 2006)
After Augustus, marriage with manus was a formal requirement only, but was still required for a formal ceremony, marking the divide between the rich and the poor in terms of the accoutrements of marriage. Still, for both rich and poor, women had little agency during much of Roman history, essentially passing from the control of their fathers to that of their husbands or their husband's fathers. "A woman married with coemptio was symbolically 'purchased' by her new husband from her father. She did not become a slave to her new husband, but he had total control over her. She was his property." (Morin, 2006) Under law, all women had to have a guardian who handled their finances and legal affairs. Marriage was the building block of Roman society, as decreed by Augustus Caesar, and founded upon the power of the father, and the eldest male in the household specifically. To encourage bachelors to marriage, Augustus "assessed heavier taxes on unmarried men and women and, by contrast, offered rewards for marriage and child bearing. Since there were more males than females among the nobility, he permitted that anyone who wished (except for senators) to marry freedwomen could do so, and decreed the children of these marriages to be legitimate," but his endorsement of marriage was hardly an endorsement of female liberation -- Augustus also allowed fathers to kill daughters and their partners in adultery, to enforce a stricter system of morality and fidelity within marriage, and to ensure the legitimacy of heirs. (Morn, 2006)
However, "things changed very rapidly towards the end of 1c AD," as the bonds of the Roman Empire and the power of paterfamilias-led families began to weaken. "Although families still lived in one home, during the Imperial Age, women could own land, run businesses, free slaves, make wills, be heirs themselves, and get a job in some professions." ("Daily Life in Ancient Rome, 2006) Society, by virtue of necessity and a dwindling population of available free males, became more inclusive, and Rome's attitudes were changed through exposure to the customs of other lands, which featured less oppressive systems of marriage, for both daughters and sons, who were not controlled by the whims of powerful paterfamilias.
Daily Life in Ancient Rome." 2006. http://members.aol.com/Donnclass/Romelife.html#FAMILIES
Morin, Lisa. "Roman Family Law and Traditions." 2006. [4 Jan 2007] http://bama.ua.edu/~morin002