That. Especially since the beginning population wasn't all that big, and back in the day there wasn't all that much mixing. Even with the class divides - which, when it comes to blood relations, didn't really mean all that much as the higher class men regularly had carnal relations with lower class women, and before contraceptives that tended to result in children more often than not - everybody with roots in the same country are more or less related.

In some ways countries, or tribes before that back then were sort of of highly extended families.

And when there was anybody more famous, like a king, known to be in the family tree, of course that knowledge was kept.

And like in all countries, your presidents have mostly come from your upper classes. From families who met each other in the parties, whose children studied in the same schools, and so on, and who, because of all that, tended to marry each other. Even if there was a bit more movement between the classes than back in the day of official nobles they presumably have stayed rather more connected anyway, as the new rising families started to marry in, and the ones that sometimes dropped out after losing their money were still related anyway.

That. Especially since the beginning population wasn't all that big, and back in the day there wasn't all that much mixing. Even with the class divides - which, when it comes to blood relations, didn't really mean all that much as the higher class men regularly had carnal relations with lower class women, and before contraceptives that tended to result in children more often than not - everybody with roots in the same country are more or less related.

In some ways countries, or tribes before that back then were sort of of highly extended families.

And when there was anybody more famous, like a king, known to be in the family tree, of course that knowledge was kept.