In linguistics, binding is the phenomenon in which anaphoric elements such as pronouns are grammatically associated with their antecedents.[citation needed] For instance in the English sentence "Mary saw herself", the anaphor "herself" is bound by its antecedent "Mary". Binding can be licensed or blocked in certain contexts or syntactic configurations, e.g. the pronoun "her" cannot be bound by "Mary" in the English sentence "Mary saw her". While all languages have binding, restrictions on it vary even among closely related languages. Binding has been a major area of research in syntax and semantics since the 1970s and, as the name implies, is a core component of government and binding theory.[1]