The Industrial Revolution led to the emergence of the middle class. As industries grew, new professions (like managers, clerks, skilled workers) developed, creating a socio - economic group between the upper (landed aristocracy, wealthy merchants before) and lower (unskilled laborers) classes. The lower class existed before (e.g., peasants), and the upper class was more traditional (aristocracy, old wealth). The middle class formed due to industrialization - related economic opportunities and social changes.