(I) Absence of Social Classes in the Tribal Stage:
In the earliest stages of social evolution i.e. in the age of primitive tribes, there were no social classes. Each individual was a .savage engaged in the struggle for survival. He used to live from hand to month and remained depended upon ‘his power’ to grab good.
However, he used to make a distinction between ‘his own members’ and ‘outsiders’. The outsiders were not tolerated. A distinction between two sexes was felt and yet equality of rank prevailed. The class division was, therefore, virtually absent.
(II) Birth of the Classes of Masters and Slaves:
As the tribes grow in their military strengths, the stronger became the masters and the weakers and dominated outsiders became the slaves. The class of slaves (members of defeated and conquered tribes) began living under the power of their captors-the masters.
The slaves were the class of powerless persons facing force and exploitation at the hands of the masters. The society came to be a stratified society with two classes-the masters and slaves.
(III) Emergence of the Class of Nobility/Feudal Lords/Patricians, and the Class of Serfs and Plebeians:
In the age of feudalism, the landed gentry (Landed Aristocracy) constituted the upper class of nobility/feudal lords/ patricians or the top class and the Serfs/Plebeians as the lower class. Slaves, household servants, artisans and even soldiers also belonged to the lower class.
With the passage of time, the artisans, the traders, the merchants and some other groups of people were in a position to become strong and independent from the control of the feudal lords and nobility. They also then got included in the upper class.
With the emergence of the industrialization, the economic power changed hands. Under the impact of the industrial resolution of the 18th and 19th centuries, the French Revolution of 1789, and American Resolution of 1779, and the birth of the age of democratic reforms, the social class structure underwent a big change.
Each society came to have several classes: Nobility, Feudal nobility, Capitalists, Peasantry, Serfs, Proletariats and the class of professionals (doctors, engineers, lawyers and others) The emergence of political and parties, ruling elites and organized classes of professional and civil servants gave a new dimension to social stratification.
There emerged a system of social positions which stood system defined as superior and inferior classes, upper and lower classes, higher and lower classes.
On the basis of economic power three-fold stratification emerged: the upper class of the rich, the lower class of the poor, and the middle class. (The middle class got further stratified into the upper middle class, the middle class and the lower middle class.
On the basis of political power, the classes came to be stratified as: the class of the powerful or power- holders, and the class of power-seekers and the class of people which does not seek power but participates in the democratic process as ‘voters’.
On the basis of social evaluation, each society has an upper class with a higher status, and a lower class with a lower status. The upper class enjoys a higher status as their role is regarded as more valuable. As such, on the basis of power each modern society comes to be a class-stratified society.