Follow up: with "divine right to rule," are some monarchies considered a form theocracy, too? Or is it just a way to legitimize a king's rule?

Are they? How do you even measure that? Is one king ruling over 1,000,000 'worth' more than twenty tribal chiefs ruling over a few hundred people each?

I have to question the assumptions in the question here.

In Roman history the desire for a smooth transition to a family member starts with Augustus, the first emperor, and later Claudius. Although military leaders were often placed in charge at times of transition they would inevitably attempt to introduce their son or heir in a coruler position so upon their death the leadership would transition smoothly, usually with the title Caesar. Although other positions had always gone to patrician "noble" families, the beginnings of the feudal system (manoroalism) were sewn with Diocleatian. His reforms resulted in serfs being tied to the land and children being forced to follow in the path of their parents. These led to the titles and nobility that supported European monarchies.