Before revision: By analogy with secular princes, in the broad sense of the ruler of any principality regardless of the style, it made perfect sense in a feudal class society to regard the highest members of the clergy, mainly prelates, as a privileged class ('estate') similar to the nobility, ranking just below or even above it in the social order; often high clerical ranks, such as bishops, were given high protocollary precedence amongst the nobility, and seats in the highest assemblies, including courts of justice and legislatures, such as Lord Bishops in the English (later British) House of Lords (where a fixed set of senior Anglican bishops and archbishops retain and use their rights to sit) and Prince primates in the Kingdom of Hungary.
After revision: By analogy with secular princes, in the broad sense of the ruler of any principality regardless of the style, it made perfect sense in a feudal class society to regard the highest members of the clergy, mainly prelates, as a privileged class ('estate') similar to the nobility, ranking just below or even above it in the social order; often high clerical ranks, such as bishops, were given high protocollary precedence amongst the nobility, and seats in the highest assemblies, including courts of justice and legislatures, such as : The Lords Spiritual (Lords Bishops of the Church of England) in the House of Lords