Римский род: структура и значение в древнем Риме.

Clan division in ancient Rome, signified by a person's nomen
the Roman family unit

In ancient Rome, a gens (/ɡ//ɛ//n//s/ or /dʒ//ɛ//n//z/, ; : gentes ) was a family consisting of individuals who shared the same nomen gentilicium and who claimed descent from a common ancestor. A branch of gens, identified by the cognomen, was called a stirps (: stirpes). The gens was an important social structure at Rome and throughout Italia during the period of the Roman Republic. Much of individuals' social standing depended on the gens to which they belonged. Certain gentes were classified as patrician, others as plebeian; some had both patrician and plebeian branches. The importance of the gens as a social structure declined considerably in imperial times, although the gentilicium continued to define the origins and dynasties of the ancient Romans, including the Emperors.

Different branches or stirpes of a gens were usually distinguished by their cognomina, additional surnames following the nomen, which could be either personal or hereditary. Some particularly large stirpes themselves became divided into multiple branches, distinguished by additional cognomina.

In theory, each gens functioned as a state within a state, governed by its own elders and assemblies, following its own customs, and carrying out its own religious rites. Certain cults were traditionally associated with specific gentes. The gentile assemblies had the responsibility of adoption and guardianship for their members. If a member of a gens died intestate and without immediate family, his property was distributed to the rest of the gens. Many gentes included both patrician and plebeian branches. These may have arisen through adoption or manumission, or when two unrelated families bearing the same nomen became confused. It may also be that individual members of a gens voluntarily left or were expelled from the patriciate, along with their descendants. In some cases, gentes that must originally have been patrician, or which were so regarded during the early Republic, were later known only by their plebeian descendants. By the first century BC, the practical distinction between the patricians and the plebeians was minimal. Nonetheless, with the rise of imperial authority, several plebeian gentes were raised to the patriciate, replacing older patrician families that had faded into obscurity, and were no longer represented in the Roman senate. Although both the concept of the gens and of the patriciate survived well into imperial times, both gradually lost most of their significance. In the final centuries of the Western Empire, patricius was used primarily as an individual title, rather than a class to which an entire family belonged.