The following is from the Official Spartacus Blog about women in the Roman Empire and in particular Gaia - who wasn't a Roman woman and why she was able to do the things she does!
As Greek culture and society developed, isolated groups and urban centers gradually developed into what the Greeks called poleis, or city-states. Often these city-states were formed by disparate groups of people, sharing little in common beyond language and the proximity of where they lived, yet over time these groups found ways to work with one another and form a new community within the city-state. The relationship found its expression in the concept of “citizenship”, the underlying idea being that the individual owed services to the community, whether in the form of holding offices or beautifying the city or serving in the military, and in turn the community would protect the person and rights of the individual.
Citizenship was closely guarded among the Greek city-states, and was only extended to those who were children of at least one citizen, sometimes two. Citizenship could not be earned; there was no “test” or “procedure” to go through to become a citizen of Athens or Sparta. You were either a member of the community, or you were not.
As with many other aspects of their culture, the Romans adopted this idea of citizenship from the Greeks and, like many other things they borrowed from the Greeks, they put their own spin on it. Early on, Romans were willing to extend citizenship to individuals, groups, tribes, even whole nations of people. It was, according to the Emperor Claudius, the greatest strength of the Roman people that they were willing to bring in to their community the best and brightest, were willing to continually evolve and adapt, and accept that other groups may have as much if not more to offer Rome than those who simply happened to have been born there. Nor were citizenship rights uniformly dispersed in a haphazard way; the Romans broke the concept of citizenship into several different rights that could be extended as one lump or piecemeal. These rights included the right to vote in Roman assemblies (ius suffragium), the right to serve in public office (ius officium), the right to hold property (ius commercii), and finally, the right to contract an official Roman marriage, draft a will, and transfer property (ius conubium).
In creating the character of Gaia in the prequel series, those “in the know” will immediately recognize that “Gaia” is not a valid Roman name for a woman; this is, in fact, because she is not a full Roman, to her advantage and disadvantage. If she were a full Roman, she would not be able to take off across the countryside and visit with Batiatus and Lucretia, and we would be utterly deprived of her company. She would have to be under the control of a male relative, or in manu to use the Latin parlance. In the Roman mind, women were like children, in constant need of guidance and direction from their more astute and intelligent male companions; to let a woman go off somewhere on her own was tantamount to unleashing an unsupervised three year old on a candy store.