In Marxist philosophy, a character mask (Charaktermaske) is a prescribed social role which conceals the contradictions of a social relation or order. The term was used by Karl Marx in published writings from the 1840s to the 1860s, and also by Friedrich Engels. It is related to the classical Greek concepts of mimesis (imitative representation using analogies) and prosopopoeia (impersonation or personification), and the Roman concept of persona, but also differs from them. Neo-Marxist and non-Marxist sociologists, philosophers and anthropologists have used character masks to interpret how people relate in societies with a complex division of labour, where people depend on trade to meet many of their needs. Marx's own notion of the character mask was not a fixed idea with a singular definition. As a psychological term, "character" is more common in continental Europe, while in Britain and North America the term "personality" is used in approximately the same contexts. Marx however uses the term "character mask" analogously to a theatrical role, where the actor (or the characteristics of a prop) represents a certain interest or function, and intends by character both "the characteristics of somebody" and "the characteristics of something". Marx's metaphorical use of the term "character masks" refers to carnival masks and the masks used in classical Greek theatre. The issue is the social form in which a practice is acted out. Sophisticated academic language about the sociology of roles did not exist in the mid-19th century. Thus, Marx borrowed from theatre and literature to express his idea. György Lukács pioneered a sociology of drama in 1909, a sociology of roles began only in the 1930s, and a specific sociology of theatre (e.g. by Jean Duvignaud) first emerged in the 1960s. Marx's concept is both that an identity appears differently from its true identity (it is masked or disguised), and that this difference has practical consequences. The mask is not a decoration, but performs a function and has effects, even independently of the mask bearer.