People who rule over others are called rulers. A ruler is also a measurement device. It turns out these "rulers" have the same origin: "a principle or maxim governing conduct, formula to which conduct must be conformed" by magnora7 in Etymology

[–]magnora7[S] 2 insightful - 2 fun2 insightful - 1 fun3 insightful - 2 fun -  (0 children)

This bit was interesting too:

c. 1200, "to control, guide, direct," from Old French riuler "impose rule," from Latin regulare "to control by rule, direct," from Latin regula "rule, straight piece of wood," from PIE root *reg- "move in a straight line," with derivatives meaning "to direct in a straight line," thus "to lead, rule."

So the words "regulated", "regulation", "regulatory", and so on all actually come from the very same latin word that "rule" and "ruler" comes from as well. I find that fascinating!