I think it is wrong to put Gaius Julius Caesar as Augustus' father. Cesar was Octavian's maternal great-uncle, not his father, see https://en.wikipedia.org/wiki/Augustus. I would like to see here Octavian's real parents.
We could do that very easily, but I'm not sure it would be a good idea.
His adoption was legally sufficient in Roman law to make him the son of Caesar, but is that what we mean now by adoption? I don't have an opinion but it's easy to see that not everyone would agree.
There is also another problem. Under the Roman law of adoption, it is only the father -- never the mother -- who is the adoptive parent.
The decision we make here would set the way we handle all of the Roman adoptions in antiquity, so it's worth taking time to discuss it and get it right.
Currently geni is allowing to record the biological, adoption and host parent-child relationship. It is true that adoption in Roman times was not the same concept as nowadays but it is still an stronger relationship than host parent and Geni is currently tracking it. So it is not consistent to keep tracking in Geni host parents relationship towards their child but avoid tracking the Roman adoption.
Morevoer, the relationship was so strong than Octavius changed his name family name from Gaius Octavius to Gaius Julius Caesar Octavianus. If our objective is to describe accurately the life of an historical character this adoption changed dramatically his life (and history). Legally, Octavius was the heir of Caesar thanks to this adoption.
So, based in both arguments: Geni tracks "lighter" relationships and the historical relevance my proposal is to track adoption in Rome.
A small correction -- there is no evidence Augustus himself ever used the name Octavianus,
Under Roman custom his new name after the adoption would have been Gaius Julius Caesar Octavianus. Father's name plus his previous nomen in cognomen form. There was no choice about that.
It is not evidence "the relationship was so strong". Instead, by calling himself Caesar rather than Octavianus he was downplaying his humble origin.
For the sake of consistency, we should also look at other cases.
For example French Field Marshall Jean-Baptiste Bernadotte was adopted by King Carl XIII of Sweden, then became Carl XIV of Sweden. Like Augustus, the adoption was a legal fiction to ensure succession. Should he also be shown on Geni as an adoptive son?
Alexander the Great was already king of Macedonia when he was adopted by a woman, Ada of Caria. Should he also be shown on Geni as an adoptive son?
Another famous case: Hans Georg Robert Lichtenberg became Frédéric Prinz von Anhalt after he paid a German princess to adopt him as an adult. He later married Zsa Zsa Gabor. Does that mean he also purchased a line of Geni ancestors going back to the Middle Ages?
Many U.S. states allow adult adoptions, including mine. Normally the adoption is for inheritance purposes only and the person does not change their name. Are those also adoptions for Geni purposes?
I think you can see this question could be more complicated than it seems at first.
PRO: All fictive relationships are genealogically significant. Adoption is adoption. It doesn't matter what purpose it served.
CON: The idea of using adoption to create a family is a modern idea that originated in the United States under specific social and economic pressures. Older forms of adoption served other, different purposes.
If you aren't already familiar with the history of adoption, a good start is Wikipedia:
https://en.wikipedia.org/wiki/Adoption
Let's throw some links in here so we alert other users to this discussion.
Alexander the Great, king of Macedonia
Charles XIV John, king of Sweden and Norway
The fact that adoption is a recent modern term is actually supporting the PRO of dealing with old adoption. In the period covered by Geni adoption was more commonly understood as Roman concept.
When I was referring to "relationship so strong" I was comparing to the "host parents" relationship which is currently tracked in Geni and is a lighter relationship (depending on the local laws, the children are not changing the surnames) than Roman adoption. My arguement was never implying that the relationship between Julius and Augustus was close.
Moreover, Geni is currently tracking as well some relationship not targeting to create a family ("host parents" and "partners").
>> In the period covered by Geni adoption was more commonly understood as Roman concept.
I don't know if that makes sense.
We have a few dozen documented cases in the ancient world where aristocrats adopted other adult men and adolescent boys who had survived the rigors of childhood.
In the ancient world most unwanted, abandoned, and orphaned children were made into slaves. Then in the medieval world they were placed in fosterage or put into monasteries and convents.
There were no legal provisions for adoption in medieval and pre-modern Europe or colonial America. The Anglo-American Common Law did not allow adoption because it was "against the natural order".
So, this argument would be that Geni added adoption support because so many users desperately wanted to show a few dozen ancient Roman relationships, not because thousands of users have modern adoptions in their extended family.
"Under the Roman law of adoption, it is only the father -- never the mother -- who is the adoptive parent."
Important - but probably possible to show by labelling the female profile: "No Adoptive Mother" or something like that.
"The decision we make here would set the way we handle all of the Roman adoptions in antiquity, so it's worth taking time to discuss it and get it right."
True - And so far it seems to me to be logically applicabl, and probably useful to apply the geni adoption option to the Roman scenarios.