The Roman definition of a gens and of a gentilis, and the line in which descent was traced should be presented before the characteristics of the gens are considered. In the _Topics_ of Cicero a gentilis is defined as follows: Those are gentiles who are of the same name among themselves. This is insufficient. Who were born of free parents. Even that is not sufficient. No one of whose ancestors has been a slave. Something still is wanting. Who have never suffered capital diminution. This perhaps may do; for I am not aware that Scaevola, the Pontiff, added anything to this definition.[286] There is one by Festus: "A gentilis is described as one both sprung from the same stock, and who is called by the same name."[287] Also by Varro: As from an Aemilius men are born Aemilii, and gentiles; so from the name Aemilius terms are derived pertaining to gentilism.[288]
Cicero does not attempt to define a gens, but rather to furnish certain tests by which the right to the gentile connection might be proved, or the loss of it be detected. Neither of these definitions show the composition of a gens; that is, whether all, or a part only, of the descendants of a supposed genarch were entitled to bear the gentile name; and, if a part only, what part. With descent in the male line the gens would include those only who could trace their descent though males exclusively; and if in the female line, then through females only. If limited to neither, then all the descendants would be included. These definitions must have assumed that descent in the male line was a fact known to all. From other sources it appears that those only belonged to the gens who could trace their descent through its male members. Roman genealogies supply this proof. Cicero omitted the material fact that those were gentiles who could trace their descent through males exclusively from an acknowledged ancestor within the gens. It is in part supplied by Festus and Varro. From an Aemilius, the latter remarks, men are born Aemilii, and gentiles; each must be born of a male bearing the gentile name. But Cicero's definition also shows that a gentilis must bear the gentile name.
In the address of the Roman tribune Canuleius (445 B. C.), on his proposition to repeal an existing law forbidding intermarriage between patricians and plebeians, there is a statement implying descent in the male line. For what else is there in the matter, he remarks, if a patrician man shall wed a plebeian woman, or a plebeian man a patrician woman? What right in the end is thereby changed? The children surely follow the father, (_nempe patrem sequuntur liberi_.)[289]