Answer: Social contract theorists, such as Thomas Hobbes and John Locke.
Details about Locke's challenge to divine right theory:
John Locke favored the idea of a "social contract." According to his view, a government's power to govern comes from the consent of the people themselves -- those who are to be governed. This was a change from the previous ideas of "divine right monarchy" -- that a king ruled because God appointed him to be the ruler.
Locke repudiated the views of divine right monarchy in his First Treatise on Civil Government (1690). Locke took aim at the arguments of a particular divine right monarchy theorist, Robert Filmer, who traced authority to rule back to Adam, the first man created by God. Locke gave logical rebuttal to show that if that if that were so, then there should only be one true heir in the world today that would rule by divine right as the one king over the whole world. (Locke also presented other reasoned arguments against divine right theory, but that's one example of how his thinking proceeded.)
In his Second Treatise on Civil Government (1690), Locke argued for the rights of the people to create their own governments according to their own desires and for the sake of protecting their own life, liberty, and property.