The term ancien Régime refers primarily to the aristocratic system that characterized French society and politics established in France under the Valois and Bourbon dynasties from the 14th century to the 18th century. It was overthrown by the French Revolution.
Power in the Ancien Régime relied on three pillars: the monarchy, the clergy, and the aristocracy. Society was divided into three Estates of the realm, the First Estate, Catholic clergy; the Second Estate, the nobility; and the Third Estate, the rest of the population.
The Ancien Régime retained many aspects of a feudal system that had existed since at least the 8th century, in particular noble and aristocratic privilege, and was supported by the doctrine of the Divine Right of Kings. The Divine Right of Kings is a political and religious doctrine of royal absolutism. It asserts that a monarch is subject to no earthly authority, deriving his right to rule directly from the will of God. The king is thus not subject to the will of his people, the aristocracy, or any other estate. It differed from that earlier feudal order in that political power had increasingly become concentrated in an absolute monarch.
About four fifths of the population were peasants and the middle class (merchants, etc).
1st Estate - Monarchy
2nd Estate - Clergy
3rd Estate - Nobility
4th Estate - peasants.