Yes, girls cannot be strong male heirs. In fact they even need a male guardian to manage their business affairs and represent them at law. Marriage and motherhood is their destiny.
But as wives and mothers, girls have the capacity to glue aristocratic families together. Suppose you are an ambitious Julius and you want to make overtures to the Sempronius family. The ultimate networking move is to marry a Sempronia, a girl imaginatively named after her family, and preferably one with a well-connected father. These unions didn’t necessarily last very long – the Romans believed in political divorce as well as political marriage. But the potential of the match went beyond the public relations coup of the wedding. If the marriage lasted, the children born into it would be of mixed Sempronius/Julius descent, they would have Julian and Sempronian grandfathers, and these patriarchs would unite for important events. Frequent intermarriage between the same families created important political bonds.
So girls could cement aristocratic families together, providing offspring with ancestry on both sides, creating shared dynasties. But that’s not all.
Romans were not impeded by Salic Law and Tail Male and all those things which in later Europe meant that property and status missed out girls and their descendants. Status in the Roman family passed in patriarchal manner from father to son, and in default of sons to brothers and so on. But property went by the will of the testator. And men without sons had a special Roman resource – adoption.
In Britain, adoption is of children, and, historically, adopted children could not enter the line of succession. So even a man as powerful as Henry VIII could not adopt a son, and ran through 6 wives and invented his own Church trying to get himself a strong male succession. Romans adopted adults. A man without a son could adopt a suitable young man to take his name. The adopted son was regarded as equivalent to a son by birth – he took on the family identity and its ancestors became his ancestors.
So where does the girl come in? Well suppose you have a daughter but not a son. When you adopt, your daughter marries the new son – this is legal. Now your grandson will be your biological heir, even if your ‘son’ isn’t. Perfect.
And what about deciding whom to adopt? Networking is a factor here. But you could also consider your own relatives on the female side – your sister’s sons for example. That way, your new ‘son’ will be biologically close to you, and importantly, descended from your own noble father. This brings us to Part 3 – Dads are Best