Dark history
Aldrich also understood that he made a joke in bad taste. The five families were the families that an Emperor was chosen from within, they were in fact Imperial families.
The bloodlines of each of them is carefully tracked and can't just be found anywhere. As one can imagine this is the subject of a long time of consideration and effort.
There were times in which these efforts have failed, unfortunately.
A long time ago when the current Republic was called the Alliance of the free cities, the magister of one of these cities used dirty methods to acquire a descendant of one of the five families.
And no one was the wiser, for twenty years the matter remained hidden. Even the boy himself had no idea of his true identity.
However, the time to pass on the imperial seat came and the old emperor performed the ceremony. To everyone's shock, no one was chosen on Ashphim.