Estates of the realm

thumb|upright=1.2|A 13th-century French representation of the tripartite social order of the [[Middle Ages – ("those who pray"), ("those who fight"), and ("those who work").]]

The estates of the realm, or three estates, were the broad orders of social hierarchy used in Christendom from the Middle Ages to early modern Europe. Different systems for dividing society members into estates developed and evolved over time.

The best known system is the French ancien régime (old regime), a three-estate system which was made up of a First Estate of clergy, a Second Estate of titled nobles, and a Third Estate of all other subjects (both peasants and bourgeoisie).
In some regions, notably Sweden and Russia, burghers (the urban merchant class) and rural commoners were split into separate estates, creating a four-estate system with rural commoners ranking the lowest as the Fourth Estate.
In Norway, the taxpaying classes were considered as one, and with a very small aristocracy; this class/estate was as powerful as the monarchy itself. In Denmark, however, only owners of large tracts of land had any influence. Furthermore, the non-landowning poor could be left outside the estates, leaving them without political rights.
In England, a two-estate system evolved that combined nobility and clergy into one lordly estate with "commons" as the second estate. This system produced the two houses of parliament, the House of Commons and the House of Lords.
In southern Germany, a three-estate system of nobility (princes and high clergy), knights, and burghers was used; this system excluded lower clergy and peasants altogether.
In Scotland, the Three Estates were the Clergy (First Estate), Nobility (Second Estate), and Shire Commissioners, or "burghers" (Third Estate), representing the bourgeoisie and lower commoners. The Estates made up a Scottish Parliament.

Today, the terms three estates and estates of the realm may sometimes be reinterpreted to refer to the modern separation of powers in government into the legislature, administration, and the judiciary. The modern term the fourth estate invokes medieval three-estate systems, and usually refers to some particular force outside that medieval power structure, most commonly the independent press or the mass media.

thumb|220px|The Three Estates of Christendom by [[Bartholomäus Bruyn c. 1535]]

During the Middle Ages, advancing to different social classes was uncommon and difficult, and when it did happen, it generally took the form of a gradual increase in status over several generations of a family rather than within a single lifetime.

One field in which commoners could appreciably advance within a single lifetime was the Church. The medieval Church was an institution where social mobility was most likely achieved up to a certain level (generally to that of vicar general or abbot/abbess for commoners). Typically, only nobility were appointed to the highest church positions (bishops, archbishops, heads of religious orders, etc.), although low nobility could aspire to the highest church positions. Since clergy could not marry, such mobility was theoretically limited to one generation. Nepotism was common in this period.

Dynamics

Johan Huizinga observed that "Medieval political speculation is imbued to the marrow with the idea of a structure of society based upon distinct orders". The virtually synonymous terms estate and order designated a great variety of social realities, not at all limited to a class, Huizinga concluded applying to every social function, every trade, every recognisable grouping.