Sui iuris is a term that derives from Latin roots, whose equivalence for our language would be "of Own Right", a word widely used in the branch of Roman law. It is understood by sui iuris or rather it is awarded as such, to that individual who at the time of the Roman Empire was not subject, dominated or subjugated by the authority or mandate of others, that is, they were not under the domination of the country power of another individual in particular. A people who were adjudicated sui iuris had the authority and power to decide on their actions, which compared people who were termed "alieni iuris" did not enjoy that right, meaning they were completely subjected under the regime of others.
Each man sui iuris was designated the paterfamilias, whether or not he had children, and whether or not he was of legal age; These male figures had full legal capacity, in addition to the famous "status libertatis", which alluded to their freedom, and the "status civitratis" which meant that they were Roman citizens. This title was granted to them when they were free of authority over them, either through the death of their male ancestors, or through emancipation.
On the other hand, the female figure could also be sui iuris, but in the case of not being under the domain of a given authority, although it could not carry out the family headship, this means that they were not allowed to carry the title of "paterfamilias". This individual, who was a free citizen and enjoyed the name of sui iuris, was also classified as an “optimal iure” person whose significance referred to the full enjoyment of each of the existing private and public rights. This had the possibility of possessing the four most important powers of Roman legislation which were: "La Patria potestas", "La Manus maritalis", La Dominica potestas and "el Mancipium".
