Four periods of development of sociological interpretations of the legitimation phenomenon are differentiated: 1) 'primordium' - initial application of the concept of legitimation (M.Weber, W.Zombart, G.Zimmel); 2) 'theses' - development of the concept of legitimation within the framework of T.Parsons' version of the structural functionalism; 3) 'antitheses' - refutation of the previous 'theses' in connection with its supposed fallibility (Mills Ch., Gouldner A., Dahrendorf R., Berger P., Luckmann T., et al.); 4) 'syntheses' - attempts to overcome intentional contradictions between 'theses' and 'antitheses', that is: theoretical dilemmas of consensus/conflict, structure/action, micro/micro-level of analysis (Luhman N., Eisenstadt S., Blau P., Habermas J., Bourdieu P., Giddens A., et al.). Legitimation as such is defined as: a) social-psychological process which involves changes of legitimacy in time; b) purposeful activity of the legitimacy creation and its development. The generalized typology of legitimation is offered; it includes such forms of the latter as religious, cultural, social, economical, political, intellectual, law, communicative, and situational legitimation. The proto-sociological ideas fruitful in constructing the concept of private property legitimation are considered, as well as those of classic and modern theoretical sociology.