How did the political ideas of the enlightenment represent a break with the ideas of Europe's past?

During the Middle Ages and the Ancien Régime, the form of political organization in Europe was the hereditary monarchy, sustained by the feudal mode of production. Inside these monarchies, political power were scattered through several political centers, with their own laws and relative administrative autonomy. Society was hierarchically organized, with almost none social mobility. This kind of political organization was radically changed by the Enlightenment idea of "social contract", which stated that political power were transferred from the people to the monarch, who, since then, ruled definitively as the unique source of rights and obligations, therefore, centralizing the political and legislative power in the king himself. Although, the king should guarantee a certain level of individual freedom, being the social contract limited by this goal.