Was a scientific law ever a hypothesis?

I understand theories and laws.A law (like adaptation) is the explanation of what happens or happened. What happens is tested repeatedly within the same conditions. Laws cannot be refuted as they are concrete and factual.A theory (like evolution) is the explanation of how and why it happens, but can be refuted at anytime if there is something substantial enough to counter it. Theories are made through the scientific method, usually starting off as a hypothesis. Theories are explanations and statements made through observation, data, and facts. A hypothesis is an explanation, without anything supporting it.Gravity is a law, because obviously we and every other object are pulled down to the surface, but I'm curious, do laws ever start out as hypotheses? Or were laws always laws?