Jus trium liberorum

The jus trium liberorum, meaning "the right of three children" in Latin, was a privilege awarded to Roman citizens who had produced at least three children or freedmen of either sex who had produced at least four children. It was a direct result of the Lex Iulia and the Lex Papia Poppaea, laws introduced by Augustus in 18 BC and 9 AD, respectively. These laws were intended to increase the dwindling population of the Roman upper classes. However, they seem to have also had an important secondary function in the rewarding of amicitia, as the "importance of legacies to Martial and Suetonius can be deduced from their (successful) efforts to obtain the jus trium liberorum"

The intent of the jus trium liberorum had led scholars to interpret it as eugenic legislation. However, most current scholarship sees the law as a politically motivated effort to increase birth rates among the senatorial class. Men who had received the jus trium liberorum were excused from munera (compulsory services). Women with jus trium liberorum were no longer subject to tutela mulierum (guardianship by a male relative) and could receive inheritances which would otherwise descend to their children.

The senatorial reaction to the jus trium liberorum was largely to find loopholes, however. The prospect of having a large family was still not appealing. A person who caught a citizen in violation in this law was entitled to a portion of the inheritance involved, creating a lucrative business for professional spies. The spies became so pervasive that the reward was reduced to a quarter of its previous size. As time went on, the jus trium liberorum was granted by consuls to some citizens as rewards for general good deeds, holding important professions or as personal favors, not just prolific propagation. Eventually the jus trium liberorum was repealed in 534 AD by Justinian.