Foucault used the “Quadrilateral of Language” metaphor to describe how language functioned in what the French called the Classic Age, roughly 1650 to 1800, the period from Descartes to Kant. His purpose was to show how the functions of language changed radically with the arrival of the Modern Age (~1800). Foucault developed his archaeological methods to investigate the impact of this change, but later revised his methods to introduce genealogical strategies to conduct “histories of the present”.
