Still looking…

Idk if [P] has been figured out yet. If not, Plantagenet is a very old, powerful name.

In the toss-up between including the Plantagenets or the Tudors, the Plantagenet’s won because much of the development of the English culture and political system (which remains to this day) arose under their rule.

https://listverse.com/2009/02/14/top-10-most-powerful-families-in-history/