Definiteness has been a central topic in theoretical semantics since its modern foundation. Two main lines of thought have classically debated about the proper analysis of definite noun phrases. One of them, initiated by Frege (1892), Russell (1905), and Strawson (1950), argues that definite descriptions crucially involve the condition – be it asserted or presupposed – that their descriptive content is satisfied by a unique entity (in the relevant context of use). The other line of thought, originally proposed by Christophersen (1939), but elaborated by Heim (1982) and Kamp (1981), claims that the core of definiteness depends on the existence of a referent in the common ground known by the speaker and the hearer.