The unicorn kingdom that existed prior to Equestria's founding had the same sort of hierarchy by lineage, and many of those titles still exist in modern times as a relic of those period. But our history had to undergo a great disruption before our current system arose.

[Celestia has picked up a common theme about royalty on other worlds. Few people have positive things to say about it. That bothers her, particularly as she remembers her own errors, frequent and egregious as they had been at first.]