Roman inheritance law was deeply connected to the family structure, particularly the concept of patria potestas - the power held by the pater familias, or head of the household. Under this system, the pater familias had legal authority over his descendants. When he died, those under his direct power became sui iuris, meaning they became legally independent. These family members, known as sui heredes or necessary heirs, were the primary inheritors of his estate and legal position.
Roman law recognized two main types of succession. Intestate succession, known as ab intestato, applied when a person died without a valid will. In this case, the law prescribed the order of inheritance. Initially, this was based on agnatic kinship, which traced relationships through the male line. Later, praetorian law and imperial legislation introduced cognatic kinship, which considered blood relationships. The second type was testate succession, or per testamentum, which occurred when a valid will existed. Romans had a strong tradition of making wills, allowing the testator to appoint heirs and distribute property. The appointed heir succeeded to the deceased's entire legal position, including both assets and debts.
Roman law distinguished between different types of heirs. Sui heredes, or necessary heirs, were those under the direct power of the deceased, such as children and grandchildren. They automatically became heirs upon the death of the pater familias and initially could not refuse the inheritance, even if it was burdened with debts. Heredes extranei, or outside heirs, were those not under the testator's power. They had to formally accept the inheritance and could refuse it if it appeared to be ruinous. In addition to appointing heirs, a testator could make specific gifts from the estate through legacies, known as legata. While heirs succeeded to the entire legal position of the deceased, including both assets and debts, legatees received only specific items without liability for debts.
While Romans valued freedom of testation, there were important limitations. First, wills had to meet formal requirements, including specific ceremonies and witnesses. Second, the testator was required to either institute or explicitly disinherit certain close relatives, particularly sui heredes. If these relatives were passed over without mention, the will could be invalidated. Third, the querela inofficiosi testamenti, or complaint of an undutiful will, allowed close relatives who were unjustly excluded to challenge the will. This led to the development of the legitima portio, or forced share, which entitled close relatives to a minimum portion of the estate, typically one-fourth. These limitations balanced the Roman value of testamentary freedom with the protection of family interests.
To summarize, Roman inheritance law was a sophisticated system based on succession to the deceased's entire legal personality, not just property transfer. The patria potestas system determined who would be the primary heirs, with those under the direct power of the pater familias becoming sui heredes. Roman law recognized both intestate succession, which applied when no valid will existed, and testate succession through a formal will. Heirs were universal successors who inherited both assets and debts, while specific gifts could be made through legacies. Although Romans valued testamentary freedom, the law imposed important limitations to protect family interests, including formal requirements, rules on institution or disinheritance, the querela inofficiosi testamenti, and the legitima portio. This system evolved over time, from the strict agnatic approach of the early Republic through praetorian reforms and imperial legislation, culminating in Justinian's comprehensive codification.