 Here, "Lemonius" is the nomen, identifying each person in the family as a member of the gens Lemonia; "Publius", "Lucius", and "Gaius" are praenomina used to distinguish between them.The origin of this binomial system is lost in prehistory, but it appears to have been established in Latium and Etruria by at least 650 BC.In written form, the nomen was usually followed by a filiation, indicating the personal name of an individual's father, and sometimes the name of the mother or other antecedents.