This was always an issue in Rome. People were afraid their heirs would turn out to secretly be wannabe dictators, and you couldn’t do anything about it since you were dead. How would you go about making sure your heir was as close to your vision as possible, both outwardly and in their desires should they be emperor?
Well, yes, I have heard about the who-wants-to-marry-my-daughter method. But I am not sure if it’s ever been done or maybe it’s just a fairy tale.