AGNATION. - In Roman law, a. was the bond uniting all free persons who were under the authority of the same paterfamilias, or who would have been under it had he not died; that is, who belonged to the same familia, or who would have belonged to it had the common paterfamilias not died. This bond was opposed to cognation (corresponding to our consanguinity [v.] or kinship), which united all and only those persons descending from a single progenitor. Therefore, unlike cognation, the bond of a. ceased for a minor who left the family through emancipation, and for anyone adopted by another paterfamilias (but Justinian distinguished between adoptio plena and adoptio minus plena, the latter of which did not remove the adopted person from his family); on the other hand, it included, for example, those adopted by the paterfamilias, who were not, however, united by a bond of cognation with the other members of the family.
(fot. Attar)
Canonists too, until the last century, used the two terms a. and cognation in the same sense that they had in Roman law. Pio Ciprotti