hold sway (over someone)
To have or exert great control or influence (over someone). My father retired from politics years ago, but he still holds sway in the town to this day. It is suspected that the president's wife holds a lot of sway over the administration's policy.
hold sway over
Dominate, have a controlling influence over, as in He held sway over the entire department. This idiom uses the noun sway in the sense of "power" or "dominion," a usage dating from the late 1500s.