The middle class is a socio-economic construction.
The ancient Hindu Varna caste system in India defined classes (jatis) vocationally as priest-scholars (Brahmins), rulers and warriors (Kshatriyas), agriculturists and merchants (Vaishyas) and artisans (Shudras). Brahmins form the upper class. The other classes were essentially strata in the middle class. Those who intermarried, nomads, foreigners, forest tribes and chandals (who dealt with disposal of the dead) were considered lower class, untouchables.
The penultimate Roman king before the founding of the Roman Empire, Servius Tullius who ruled from c.578 until his assassination by his own son in 535 BC, divided citizens into classes according to wealth. The upper class was the classici. Soldiers (aged 17 to 45) and urban police (over 45) were selected from the upper class. The lowest class was the proletarii who owned no estate. In between were four infra classem, the lowest dedicated to certain artisans including carpenters. The power to vote in the comitia centuriata, summoned by the Senate, depended on social class.
Thomas Stevenson (1870--1932), Superintendent of Statistics in the United Kingdom General Register Office, is accredited with creating the first modern class-based classification system. The 1911 United Kingdom Census tables on Fertility of Marriage used occupation-based grades labeled "social classes." From 1990, these were referred to as "Social Class based on Occupation." Stevenson's middle class referred to professionals and skilled workers. The most common definition of the middle class remains occupation based.
In the United Kingdom, ownership of the family house also became a characteristic of the middle class. Non-urban middle-class towns in England, such as the Kentish town of Tunbridge Wells, are sometimes described as Middle England.
In the United States, many families consider themselves middle class, own their own home and send their children to college, although the primary income-earner is employed in manual, blue collar work. Income is one of the primary indicators of social class in the United States. Income statistics are compiled by the Bureau of Economic Analysis by individual, and by the Census Bureau by household. In 2008, 48 percent of individuals had incomes between $25,000 and $82,500 a year. In 2003, 44.92 percent of households earned between $25,000 and $75,000. In 2008 42 percent of households had two or more income-earners. The phrase Middle American is used to refer to conservative politics like family values. C.Wright Mills (1916--1962) carried out one of the first American sociological class studies in America White Collar: The American Middle Classes (1951). He considered city workers oppressed because of the lack of opportunity for independence and their inability to affect or change the world.
In Das Capital (1871) Karl Marx (1818–1883) and Friedrich Engels (1820--1895) described the middle class as living on profit. They contrasted the middle class with the working class, who live on wages, and the land owning aristocracy, who have inherited wealth or live on ground rent. Marxists refer to the middle class by the French term bourgeoisie meaning "the trading middle class." In The Communist Manifesto, Marx and Engels defined the bourgeoisie as the employers of wage labor. This was because they considered the bourgeoisie the owners of capital in society -- the means of social production. Communists consider the classes in a constant struggle, with workers trying to break free from the control of their employers, the middle class owners of capital.
The Russian revolutionary leader Vladimir Lenin (1870–1924) widened the concept of the bourgeoisie to include anybody living on income from capital and real estate, as well as academics, and military or civil officials. Lenin included owners of small properties who did not employ significant labor, workers in supervisory positions, and lower management including departmental managers and foremen. He described these as the "petty bourgeoisie."
The prominent sociologist Max Weber (1864–1920) recognized four principal classes: the upper class, white collar workers, the petite bourgeoisie and the manual working class. Weber distinguished socio-economic stratification based on income (employment) and investments (capital), from social hierarchies based on status and power.
Besides occupation and property ownership, the middle class can be categorized as typically having "human capital," vocational education. Middle-class adolescents typically attend post-compulsory, higher education. Many obtain professional qualifications. In the late 20th and early 21st centuries, the information age, the middle class were considered the most influential class in respect of media control. Teachers, authors, journalists, media editors, television presenters, critics, academics, economists and entertainment professionals, who are essential in shaping public opinion, are mostly considered members of the professional middle class.