The article presents a brief history of the concept of generations. It focuses on Karl Mannheim’s article "Problems of Generations" (1928), its social origins and theoretical content. Mannheim’s role was crucial in 20th century development of the (new) concept of generation. In order to understand the problem of social (historical) generations and evaluate Mannheim’s position within the concept’s development, several points are discussed in more detail: the history of the concept of "generations", the relationship between class and generation, and how ideas about the formation of generations help us to understand social dynamics over time. In doing so we assume that the origin of Mannheim’s lecture lies in the generational experience of Hungarian intellectuals during the collapse of the old order of the Dual Monarchy and the Revolution of 1918-19. The Budapest intellectual life in the 1910s was important for Mannheim’s "Problems of generations", as well as A. Weber’s cultural sociology. Finally, the article analyzes the migration of the generations concept from one culture (Germany) to another (the United States), and from one discipline (sociology) to another (memory culture).