In the middle ages, the bloodline was seen as very important. but in the Roman Empire that came before, it was not only Emperors who would have adopted sons as heirs, but it can be seen that owners of large estates did that too.
So why didn't it continue into the 800s? Boarders might change as Rome becomes no more, but what made the noble class to decide to be picky on bloodlines? Why didn't Europe have something like Mukoyōshi like the Japanese did (or the Romans before them)?
Let's say the divine right of kings existed as a concept. OK, but Roman Emperors ruled through the pagan days and Christianity and in the eyes of loyalsits ruled with the gods'/the Lord's approval and while it was united as an entity people didn't question adoption. I'm not saying everyone has to resort to that if they find themselves without a biological offspring (I'm sure some brother, sister, uncle, or cousin can do as a heir) but why is the adoption option gone?
So why didn't it continue into the 800s? Boarders might change as Rome becomes no more, but what made the noble class to decide to be picky on bloodlines? Why didn't Europe have something like Mukoyōshi like the Japanese did (or the Romans before them)?
Let's say the divine right of kings existed as a concept. OK, but Roman Emperors ruled through the pagan days and Christianity and in the eyes of loyalsits ruled with the gods'/the Lord's approval and while it was united as an entity people didn't question adoption. I'm not saying everyone has to resort to that if they find themselves without a biological offspring (I'm sure some brother, sister, uncle, or cousin can do as a heir) but why is the adoption option gone?